Unit 1

Question 1

Describe the functions of the CV system

Answer 1

• distribute dissolved gases (like O2) and nutrients
• remove metabolic waste
• maintains homeostasis (controls temp., pH, electrolytes)

Question 2

Describe the series and parallel arrangement of the circulatory system, and its purposes

Answer 2

• right and left sides of heart arranged in series (one after another)
• systemic circulation can be parallel so that multiple organs are supplied at the same time (branching)

Question 3

Describe the anatomy of the heart, including its chambers, valves, and major vessels

Answer 3

• epicardium: outer layer of CT and fat
• myocardium: middle layer of muscle
• endocardium: inner layer of endo cells
• pericardium surrounds entire heart; fluid filled
• four chambers: left and right atria and ventricles
• mitral valve between left atrium and ventricle
• tricuspid valve between right atrium and ventricle
• aortic valve between left ventricle and aorta
• pulmonary valve between right ventricle and pulmonary artery
• vena cava drains into right atrium

Question 4

Describe the blood flow pathway through the heart

Answer 4

blood is oxygenated in lungs –> pulmonary vein –> left atrium –> mitral valve –> left ventricle –> aortic valve –> aorta –> body –> vena cava –> right atrium –> tricuspid valve –> right ventricle –> pulmonary valve –> pulmonary artery –> lungs to get reoxygenated

Question 5

Describe the major types of blood vessels

Answer 5

• pulmonary vein: carry oxy blood from lungs to heart
• pulmonary artery: carry deoxy blood from right ventricle to lungs
• aorta: carry oxy blood from left ventricle to body
• vena cava: carry deoxy blood from body to right atrium

Question 6

Describe the arrangement of the microcirculation

Answer 6

• vasculature from the first order arterioles to the venules
• site of gas, nutrient, and waste exchange
• precapillary sphincters: smooth muscle bands at junctions of arterioles and capillaries
• no smooth muscle, just endo cells and basement membrane

Question 7

Describe the function of the lymphatic system

Answer 7

• lymph is excess interstitial fluid
• flows through lymph vessels to lymph nodes and rejoins circulatory system
• edema occurs when interstitial fluid exceeds capacity of lymphatic system

Question 8

Describe the cardiac conduction system

Answer 8

SA node –> atria through gap junctions –> AV node (delay) –> His-Purkinje fibers

Question 9

Why are arterioles so special?

Answer 9

• thicker than aorta and arteries
• highly innervated by autonomic nerves, circulating hormones, and local metabolites
• main site of regulation of vascular resistance by changing size of diameter

Question 10

Describe the anatomy of vessels

Answer 10

Tunica adventitia:

• outer layer
• mostly CT with collagen and elastin

Tunia media:

• middle layer
• innervated smooth muscle
• controls diameter

Tunica intima:
- single layer of endothelial cells

Question 11

What are intercalated disks?

Answer 11

• connect cardiac myocytes to transfer force and coordinate electrical activity

Question 12

What is the relationship between pressure, flow, and resistance in the circulatory system?

Answer 12

• Flow is volume per unit time (Q); constant throughout system and equal to CO in CV system

Flow = Velocity*Cross-sectional Area
AND
Flow = pressure difference/resistance
OR
CO = (MAP-VP)/TPR

• analogous to I = V/R

Question 13

How do changes in vascular resistance determine distribution of CO among tissues?

Answer 13

• if you change the diameter of a vessel through vasoconstriction or vasodilation, then according to Poiseuille’s Flow, you can drastically affect flow through that vessel

Question 14

How do vascular resistance, blood viscosity, vessel length, and vessel radius affect blood flow?

Answer 14

Flow = pressure diffpiradius^4/(8viscositylength)
OR
Q = deltaPpir^4/(8nl)

• key point is that radius is ^4

Question 15

How is the pulsatile flow of blood converted to steady flow in capillaries?

Answer 15

• elastic walls of aorta and arteries dampen pulsatile pressure, so by the time they reach capillaries, more like a continuous flow
• helps because pulsatile needs more work (accelerating mass vs constant vel)

Question 16

What is vascular compliance?

Answer 16

C = deltaV/deltaP

• represents the elastic properties of vessels (if very compliant, then easily expanded, like veins but not arteries)
• compliance is opposite to elasticity
• determined by elastin fibers vs smooth muscle and collagen in vessel walls
• more compliance = lower pulse pressure (can expand more so doesn’t maintain pressure as well)

Question 17

What is the relationship between vascular wall tension, transmural pressure, radius, and wall thickness?

Answer 17

Wall tension = transmural pressureradius/wall thickness
OR
T = deltaPtmr/u

• Wall tension is the circular tension that exists around/on the wall of a vessel

Question 18

What is Fick’s Principle and how can it be used to determine transcapillary efflux?

Answer 18

• Fick’s principle: the amount used is the equal to the amount that enters minus amount that leaves

x_used = xi-xo = Q*([x]i-[x]o)

for myocardial O2 consumption:
mVO2 = CO*([O2]arterial-[O2]venous)

Question 19

How does the balance between hydrostatic and oncotic pressures in a capillary bed determine direction of transcapillary transport?

Answer 19

• hydrostatic pressure is difference between capillary blood pressure and interstitial pressure and typically results in stuff going out of vessel into interstitium (because pressure there is basically 0) –> filtration
• oncotic pressure is due to osmotic force by proteins; more proteins in blood, so fluid comes into vessel –> reabsorption

Flux = k[(Pc-Pi)-(pic-pii)]

• Arterial side of capillaries, Pc is higher and pic is lower; opposite for venous side

Question 20

What is transmural pressure?

Answer 20

• Difference in pressure between inside and outside of a vessel (across the wall)

Question 21

Where does pressure fall the most?

Answer 21

• Arterioles

Question 22

What is the total blood volume? Where is most of the blood volume found?

Answer 22

• about 5L

- Mostly in venous system

Question 23

Describe resistance, flow, and pressure in parallel and in series

Answer 23

Parallel:

• 1/Rtot = 1/R1+1/R2+….
• deltaP1 = deltaP2 = …
• total res is lower than individual paths
• changing one res pathway doesn’t affect total res that much
• pressure diff is same across all branches
• flow is proportional to 1/Ri

Series:

• Rtot = R1+R2+….
• Q1=Q2=….
• total res is sum of res (most res in arterioles)
• flow is constant, but pressure diff is different between segments

Question 24

Difference between laminar and turbulent flow

Answer 24

• Laminar: smooth, efficient, slowest at edge, fastest in center
• Turbulent: irregular; needs more pressure for same avg velocity; occurs with large diameter, high velocity, low viscosity, changes in diameter; creates shearing force that damages endo cells

Question 25

What is mean arterial pressure?

Answer 25

diastolic pressure + 1/3(systolic press-diastolic press) OR 1/3systolic press + 2/3diastolic press - basically like this because more often in diastole than in systole --> changes with heart rate

Question 26

What is bulk transport?

Answer 26

- cargo from point A to point B in the CV system; can use to measure O2 consumption rate = flow*conc OR x=Q*[x]

Question 27

What are the unique properties of cardiac muscle?

Answer 27

- striated - autonomic (doesn't need neural input) - interconnected mono-nuc cells in weaved collagen - longer repol than skeletal muscle - ATPase activity slower than skeletal - **thin-filament regulated (as opposed to thick for smooth muscle) - mechanical and electrical coupling between cells (desmosomes provide mech coupling, gap junctions for electrical) - lots of mitochondria

Question 28

Describe the cross bridge cycle

Answer 28

- resting muscle: low Ca in cell, TN-TM complex inhibits actin-myosin binding; action potential leads to release of Ca from SR to increase Ca in cell; TN binds Ca and moves TM out of the way so actin and myosin can bind 1) ATP binds and hydrolyzes to ADP and Pi to activate myosin; Pi leaves and myosin strongly binds to actin 2) ADP released and myosin head pivots 3) ATP binds to myosin head and detaches 4) reactivate myosin head with hydrolysis of ATP

Question 29

Describe the length tension (Frank-Starling) relationship in cardiac muscle

Answer 29

- increase in preload --> increase in SV - length-tension relationship (some optimal length where if you lengthen the sarcomere, get a better overlap, better Ca sensitivity, and inc Ca release and a better contraction --> increased preload stretched the sarcomeres)

Question 30

Relate myocyte mechanics to ventricular function

Answer 30

- inc in volume --> inc in ventricular circumference --> inc in length of individual myocytes - T=P*r/u

Question 31

Identify sarcomeric changes associated with heart failure

Answer 31

- hypertrophy: concentric cell growth; changes mainly in Ca sensitivity - Dilation: eccentric cell growth; changes in force output

Question 32

What is cardiac output?

Answer 32

CO = stroke volume*heart rate

Question 33

What factors control stroke volume?

Answer 33

- Preload: length-tension; higher preload = higher force - Afterload: pressure that ventricle needs to overcome; usually aortic pressure - Contractility: force that heart contracts with; norepinephrine regulates

Question 34

What are the proteins involved in contraction?

Answer 34

- Myosin: 2 heavy and 4 light chains - Actin: binds tropomyosin and troponin - Thin filament regulatory proteins: - - TN-C: contains one Ca binding site - -TN-I: regulated by phosphorylation/PKA sites; actin cannot bind myosin when in the way - -TN-T: binds tropomyosin - -Tropomyosin: lays over actin in the myosin binding sites

Question 35

Describe titin

Answer 35

- giant protein - functions as an elastic spring - resting tension of myocyte - N2B is stiffer and shorter than N2BA

Question 36

Define cardiac output

Answer 36

- CO is the volume of blood pumped per min by the left ventricle CO=SV*HR - usually about 5L/min at rest

Question 37

What are the four phases of the cardiac cycle and describe changes in pressure and volume in each chamber accordingly

Answer 37

1) Diastole: - LA filled with oxy blood and mitral valve is open so LV fills with blood passively - LA contracts and builds atrial pressure - mitral valve is open and blood starts to fill in LV and also increase pressure in LV 2) Isovolumetric contraction: - LV contracts as pressure increases really quickly - volume stays same because mitral valve closed when filled enough and aortic valve not open yet 3) Ejection phase: - LV contracts and aortic valve opens - LV starts to relax and ejects blood so pressure starts to decrease and volume decreases - aortic valve stays open for a little bit due to inertia of blood moving while LV relaxes 4) Isovolumetric relaxation phase: - aortic and mitral valves closed and LV continues to relax so volume is same, but pressure decreases until so low that mitral valve opens again

Question 38

Define systolic and diastolic pressure-volume relations and ventricular function curves

Answer 38

End diastolic pressure-volume relationship (EDPVR): - represents the preload on the heart - curve representing pressure-volume relation while passive, before contracting (at the end of diastole) Systolic pressure-volume relationship (SPVR): - curve representing pressure-volume relation at peak of contraction - depends on afterload (aortic pressure)

Question 39

Describe the Frank-Starling Law of the Heart

Answer 39

1) if increase in EDV, then increase in force of contraction 2) healthy heart functions on ascending limb of Starling curve 3) CO must equal venous return; CO from LV and RV must match - titin is stiff - as sarcomeres are stretched, more Ca binding sites, so more contraction - closer lattice spreading

Question 40

Describe relative changes in pressure and volume through the cardiac cycle (PV Loops)

Answer 40

1) Filling phase: - ESV is bottom left; lowest pressure and lowest volume right after systole - LV relaxes and fills with blood passively from LA with little change in pressure - end volume is end diastolic volume 2) Isovolumetric contraction phase: - LV contracts, mitral valve closed, but aortic valve alos closed since LV pressure not high enough to over come yet, so volume stays same 3) Ejection phase: - LV pressure exceeds aortic pressure so aortic valve opens - blood leaves so volume decreases - pressure increases because blood cannot leave aorta as fast as it enters - pressure starts to fall as LV starts to relax 4) Isovolumetric relaxation phase: - LV pressure below aortic pressure, aortic valve closes, still relaxing so mitral valve still closed

Question 41

Define stroke volume, ejection fraction, stroke work, and pulse pressure, and to identify them graphically on a PV Loop diagram

Answer 41

Stroke Volume: - amount of blood pumped per beat - EDV-ESV = SV Ejection Fraction: - fraction of EDV ejected during systole - SV/EDV = EF Stroke Work: - energy per beat - area of PV loop Pulse Pressure: - systolic pressure - diastolic pressure

Question 42

Define preload, afterload, and contractility, and describe how altering these variables changes ventricular function

Answer 42

Preload: - EDV; the amount that initially stretches the LV - *ventricular compliance: dec compliance = more stiff (hypertrophy) = lower EDV at given pressures (shifts EDPVR left) - if you inc preload, you immediately increase SV (Starling's law) bc EDV increases but ESV stays same and stroke work inc - next beats are same SV because ESV is same Afterload: - ~aortic pressure - wall thickness and radius affect - inc afterload, decrease in SV because less time for ejection (since need to reach higher pressure before aortic valve opens), also less pressure due to dec shortening velocity and lower ejection velocity - EDV is same, EF dec, ESV inc, SV dec Contractility: - strength of contraction indep of preload or afterload - new Startling curves - regulated by drugs and NS - if inc inotropy, shift Starling curve to left (greater systolic pressure at any vol); see inc SV, dec ESV, inc EF

Question 43

How do HR and SV affect CO?

Answer 43

CO=HR*SV - HR is highly regulated by autonomic NS - HR can change more than SV so can influence CO more - high HR means less time for filling --> lower stroke volume - SV affected by preload, afterload, and contractility

Question 44

What is active tension?

Answer 44

- the difference in force between peak sys press and dia press curves - basically the tension developed purely by contraction, indep of preload - presented by Starling Curve

Question 45

Describe the differences between fast and slow cardiac APs graphically

Answer 45

Slow APs: - Phase 0: rising phase due to Ca channels - no Phase 1 or 2 - Phase 3: repol due to IKr and IKs (delayed rectifier K channels) - Phase 4: steady depol from If Fast: - Phase 0: rising phase due to Na channels - Phase 1: IKto gives a partial repol and makes Ca entering more favorable - Phase 2: plateau phase where L type Ca channels open - Phase 3: delayed rectifier IKr and IKs channels open to repol - Phase 4: flat, some inward rectifier

Question 46

Which cells are fast and slow cardiac APs found in respectively?

Answer 46

Fast: - atrial muscles - ventricular muscles - Purkinje fibers Slow: - SA nodal cells - AV nodal cells

Question 47

Describe the properties of ion channels that underlie fast and slow cardiac APs

Answer 47

Fast APs: - Phase 0: rapid depol of entry of Na ions - Phase 1: partial repol due to inact of Na gates and act of IKto - Phase 2: plateau where L-type Ca channels are open influx are balance by IKr and IKs - Phase 3: Ca gates start to inact and act of IKr and IKs - Phase 4: IKr and IKs deact and IK1 holds Vm near Ek Slow: - Phase 0: upstroke due to Ca channels and not as fast as Na - no phase 1 or phase 2 - Phase 3: IKr and IKs cause repol - Phase 4: slow depol that brings cell back to threshold automatically due to funny current --> activated by hyperpolarization after IKr and IKs --> brings in Na and out K, but mainly in Na so depols slowly

Question 48

Describe the ionic mechanisms that account for the ability of pacemaker cells to generate firing without neural input

Answer 48

- repetitive slow APs due to If causing a slow depolarization naturally

Question 49

Describe the significance of IK1 channels in myocardial cells with fast APs

Answer 49

- maintain resting membrane potential around EK after AP

Question 50

Describe the significance of If or Ih currents in cells with slow APs

Answer 50

- causes the slow depol that allows cells in SA and AV node to fire automatically

Question 51

Discuss the mechanism and significance of overdrive suppression

Answer 51

- Overdrive suppression is when AV node cells reach APs with a higher frequency than naturally because of signals from the SA node, which generates APs faster than the AV does naturally

Question 52

Define the absolute refractory period

Answer 52

- 2nd AP cannot be initiated until most of Na inactivation is removed (during repol phase)

Question 53

Define the relative refractory period

Answer 53

- threshold is elevated for an AP until after repol phase due to compete removal of Na inactivation and complete deactivation of IKr and IKs)

Question 54

Describe Na channels

Answer 54

- depol causes rapid activation then voltage-dep inactivation -

Question 55

Describe Ca channels

Answer 55

- similar to Na channels - L type: long; high depol causes rapid activation then voltage-dep and cytoplasmic Ca-dep inactivation; mainly in cardiac muscle - T type: transient; low depol activated then inactivate

Question 56

Describe time-dep K channels

Answer 56

IKto: - transient outward - depol leads to act and inact slower than Na channel - Phase 1 of fast APs IKr and IKs: - rapid and slow delayed rectifier - depol leads to activation - Phase 3 of fast and slow APs

Question 57

Describe the inward rectified K channels

Answer 57

IK1: - conduct inward K current when VmEk - hold cells near Ek between APs

Question 58

Describe the funny current

Answer 58

- turned off at depol and turned on at hyperpol | - permeable to both Na and K (Erev = -30)

Question 59

What is HERG?

Answer 59

- anti-target for new drugs - IKr is a tetramer of HERG and important for repol in both fast and slow APs - altered HERG can lead to arrhythmias

Question 60

How do electrical impulse spread from cell to cell

Answer 60

- through gap junctions between cells, there are connexins that let ions pass

Question 61

Describe the cardiac conduction pathway

Answer 61

starts in SA node in high RA --> RA --> LA (P wave) --> AV node b/w tricuspid and mitral valves b/w atria and ventricles (junction) --> delay before entering ventricles --> bundle of His --> left and right bundle branches --> Purkinje fibers

Question 62

Compare ventricular AP to an ECG

Answer 62

- Phase 0 = QRS - Phase 2 = ST segment - Phase 3 = T wave - Phase 4 = isoelectric segment

Question 63

What is T wave and QRS in the same direction but repol and depol not?

Answer 63

- Endocardium depol earlier than epicardium, but repol later than epicardium - so repol going away from the electrode looks like a positive deflection

Question 64

Describe the components of the ECD

Answer 64

- P wave = atrial depol - QRS = ventricular depol - T wave = ventricular repol - PR interval = index of conduction time across AV node - QT interval = total duration of depol and repol

Question 65

What happens with SA node abnormality?

Answer 65

- slow sinus rate | - taken over by other pacemakers that can be too fast or too slow

Question 66

Describe the types of AV block

Answer 66

1st degree: conduction delayed but all P waves conduct to ventricles 2nd degree: some P waves conduct 3rd degree: no P waves conduct; ventricular pacemaker takes over

Question 67

Describe the different bundle branch blocks

Answer 67

Right bundle blocked: wide QRS w/ delayed conduction to right ventricle Left bundle blocked: wide QRS w/ delayed conduction to left ventricle Left fascicles blocked: shifts in depol, but no wide QRS

Question 68

What are the 3 common mechanisms leading to arrhytmia?

Answer 68

1) abnormal reentry pathways: - unidirectional block and slowed conduction 2) ectopic foci: - focus of myocardium acquires automaticity and rate is faster than SA node 3) triggered activity: - afterpolarizations due to preceding AP

Question 69

Describe the gene defects and molecular basis of long QT syndrome

Answer 69

- mutations in cardiac ion channels - AD form (Romano-Ward syndrome): 200+ mutations mainly in IKs, IKr, and Na channels - AR form (Jervell-Lange-Nielson syndrome): mutations in IKs also have deafness - mutations in K channel subunits (LQT1) --> reduce number of K channels expressed --> reduced size of IKr and IKs current --> weaker repol --> longer plateau - mutations in Na channels (LQT3) prevent them from inactivating completely --> prolong phase 2 due to more depol

Question 70

List the cardiac ion channels and the phases of the slow and fast responses that are targeted by the various antiarrhythmic drugs

Answer 70

Ion channel targets: - Na channels - Ca channels - K channels (IKr and IKs) - beta-adrenergic receptors - Na channel blockers for LQT3 due to elongated phase 2 - K channel openers for LQT1 or LQT2 but none currently exist

Question 71

Describe the cellular mechanism of triggered (early and delayed) afterdepolarizations

Answer 71

EAD: - during late phase 2 and phase 3 - re-activation of Ca channels due to elevated Cai from prolonged phase 2 DAD: - during early phase 4 - inc Cai --> inc Na/Ca exchange (3 Na in/1 Ca out) --> depol due to Incx

Question 72

Describe how a re-entrant, or circus, arrhythmia originates

Answer 72

- two requirements: 1) uni-directional conduction block 2) conduction time around the circuit is longer than refractory period -

Question 73

Describe the basis of use-dependent block of Na channels by class I antiarrhythmic drugs

Answer 73

- drugs target cells that are over-active with high firing rates or that are abnormally depolarized - this targets defective cells and prevents affecting normal cells - hydrophilic drug enters pore when channel is open

Question 74

Describe how class I antiarrhythmics increase Na channel refractory period, whether or not they prolong phase 2 of the fast response

Answer 74

- drug initially blocks and enter channel during open state, but have a higher affinity during closed state and stabilize that closed/inact state and prolong the time the channel spends in the inact state - class Ia and Ic drugs block K channels to delay repol and prolong phase 2 --> more Na channels are inact --> longer refractory period

Question 75

Describe how beta-adrenergic receptor blockers help suppress arrhythmias

Answer 75

- reduce If, ICa, and IKs current --> reduce rate of diastolic depol in pacemaker cells, reduce upstroke rate, and slow repol --> pace rate is reduced and refractory period is prolonged - AV nodal re-entry terminated - control ventricular rate during afib - dec phase 4 slope --> dec rate of firing --> dec automaticity - prolonged repol of AV node --> inc effective refractory period --> dec re-entry

Question 76

Describe how class III drugs increase refractory period

Answer 76

- block IKr channels - leads to prolonged phase 2 and prolonged refractory period - inc effective refractory period --> dec re-entry

Question 77

Describe how class IV antiarrhythmic drugs (Ca channel blockers) reduce re-entry via effects on conduction velocity through the AV node and refractory period of the AV node

Answer 77

- block Ca channels --> slows Ca upstroke in slow AP cells --> slows conduction velocity in AV node --> dec re-entry - prolong refractory period --> dec re-entry - also, since reduced peak Ca upstroke, you have reduced K repol

Question 78

Describe how increasing refractory period may help suppress re-entrant arrhythmias

Answer 78

- tissue in refractory period cannot generate an AP so the re-entrant arrhythmia would be extinguished

Question 79

Describe how some antiarrhythmic drugs can suppress arrhythmias by decreasing cardiac automaticity

Answer 79

- class II beta blockers block If so that rate of depol during diastole is reduced and rate of firing (decreasing cardiac automaticity) is decreased --> slows conduction velocity --> dec re-entry

Question 80

Describe how adenosine can help suppress cardiac arrhythmias

Answer 80

- through GPCR (similar mechanism to beta blockers), can inc K current, and dec Ca and If currents - dec If and ICa --> dec diastolic depol and weaker upstroke --> slowed conduction velocity - adenoside binds to receptor --> activated G protein --> inhibits cAMP --> reduces cAMP --> reduces PKA --> reduces phosphorylation of Ca channels --> closes Ca channels --> smaller Ca current --> smaller upstroke - G protein binds to IKado --> inc in K current --> faster hyperpol

Question 81

What happens in long QT syndrome?

Answer 81

- prolongation of the plateau phase 2 of fast AP cells in ventricular myocytes --> ventricular tachycardia (torsades de pointes) --> ventricular fibrillation --> syncope --> sudden cardiac death

Question 82

What is Brugada syndrome?

Answer 82

- form of congenital arrhythmia - ventricular fibrillation occurs - 30+ different mutations in Na channels --> reduce peak inward Na current

Question 83

What happens in Finnish familial arrhythmia?

Answer 83

- beta-adrenergic receptors upregulate Ca channels, but not K channels - yotiao normally targets PKA of Ca and K channels by binding to them - however binding to K channels is impaired --> diminished beta receptor upreg of K channels - with sympathetic activity, Ca depol, but not enough K repol

Question 84

What are the two sources of arrhythmias?

Answer 84

1) inappropriate impulse initiation in SA nodes: - ectopic foci (SA node too slow or ectopic foci too fast) - EADs (depol during phase 2/3 from Ca) - DADs (depol during phase 4 from Ca and NCX) 2) disturbed impulse conduction in nodes, conduction (Purkinje) cells, or myocytes: - conduction block (1, 2, 3 degree) - re-entry (requires uni-directional conduction block and conduction time around circuit is longer than refractory period)

Question 85

What is the primary mechanism of class I drugs?

Answer 85

- blocking voltage-gated Na channels (slower upstroke) - affect fast response cells mainly - decrease conduction rate and increase refractory period - block Na channels --> dec phase 0 upstroke velocity --> dec conduction velocity --> dec re-entry - inc effective refractory period --> dec re-entry

Question 86

Describe class Ia Na channel blockers

Answer 86

- slowed upstroke (block of Na channels due to class I) - delayed repol (block of K channels due to class III) - prolonged refractory period

Question 87

Describe class Ib Na channel blockers

Answer 87

- slowed upstroke (block of Na channels due to class I) - prolonged refractory period - phase 2 NOT prolonged, actually shortened - purest form of class I (because only Na channel block and not K channel)

Question 88

Describe class Ic Na channel blockers

Answer 88

- most pronounced slowed upstroked - prolonged phase 2 - powerful prolongation of refractory period

Question 89

What are two mechanisms to terminate re-entry?

Answer 89

1) slow AP conduction velocity --> reduce upstroke rate --> more likely to fail to propagate through depressed region --> convert to bi-directional block 2) prolong refractory period --> refractory tissue will not generate an AP

Question 90

What is the paradox in combating re-entry?

Answer 90

- try to slow conduction velocity, but this means that the signal being propagated is less likely to be shorter than the refractory period, meaning that it will be able to excite tissue since they will no longer be in the refractory period

Question 91

What is so special about Amiodarone?

Answer 91

- class III antiarrhythmic but has class I activity - reduces conduction velocity because blocks Na channels - also dec rate of diastolic depol (phase 4) in pacemaker cells - dec conduction velocity --> dec re-entry - dec rate of firing --> dec automaticity

Question 92

How do you treat paroxysmal supraventricular tachycardia?

Answer 92

acute: adenosine (short half-life) chronic: AV node blockers (class II, class IV, class II, digoxin), cather ablation of ectopic foci

Question 93

How do you treat atrial fibrillation?

Answer 93

acute: AV node blockers, electrical cardioversion chronic: AV node blockers with anticoag (warfarin), cardioversion with maintaining sinus rhythm with drugs (class III, class Ic)

Question 94

How do you treat ventricular tachycardias/fibrillation?

Answer 94

prevent sudden cardiac death acute: amiodarone, lidocaine, pocainamide chronic: beta-blockers, mabye amiodarone

Question 95

What is the half-life of class II esmolol?

Answer 95

10 min

Question 96

What is the half-life of class II amiodarone?

Answer 96

13-100 days

Question 97

What is the half-life of adenosine?

Question 98

What are class I antiarrhythmic drugs?

Answer 98

block Na channels

Question 99

What are class II antiarrhythmic drugs?

Answer 99

beta blockers

Question 100

What are class III antiarrhythmic drugs?

Answer 100

block K channels

Question 101

What are class IV antiarrhythmic drugs?

Answer 101

block L-type Ca channels

Question 102

Describe the mechanisms by which PKA-mediated phosphorylation of Phospholamban, L-type Ca channels, RyRs, and troponin I affect inotropy and lusitropy

Answer 102

Phospholamban: - PB inhibits SERCA - when phos, PB dissociates from SERCA, so SERCA reuptakes more Ca into SR - inc lusitropy (better relaxing) - inc inotropy by inc SR Ca load L-type Ca channels: - phos of these channels slows inactivation so more CICR and inc inotropy RyRs: - when phos, more sensitive to Ca (less Ca for same Ca release) - inc inotropy Troponin: - normally, TnI inhibits interaction between actin and myosin - when phos, decrease sensitivity of Ca --> faster dissoc of Ca --> inc lusitropy --> heart fills more quickly

Question 103

Describe how HCN, L-type Ca, RyRs, and GIRK channels contribute to autonomic control of heart rate

Answer 103

HCNs (hyperpolarization-activated cyclic nucleotide-gated channels): - symp stim: inc cAMP --> cAMP bind directly to HCN channels to make them more likely to open --> more If to inc rate of diastolic depol --> inc heart rate - para inh: dec cAMP --> HCN less likely to open --> less If to dec diastolic depol --> dec heart rate L-type Ca: - symp stim: cAMP activates PKA --> phos L-type Ca channel --> slows inactivation --> inc Ca current --> inc heart rate - para inh: dec cAMP --> PKA less activated --> less phos of LTCCs --> no slowing of inact --> dec/normal Ca current --> dec heart rate RyRs/NCX: - symp stim: inc SR Ca load when PKA phos PB, RyRs, and LTCCs --> more Ca release --> diastolic depol with more inward current from NCX --> inc heart rate - para inh: less Ca release --> less diastolic depol with less inward current from NCX --> dec heart rate GIRK (G-protein couple inwardly-rectifying K): - para inh: beta/gamma Gsubunit binds to GIRK --> activated IKACh --> keep Vm near EK --> slow firing freq --> dec heart rate

Question 104

Describe the differences between vascular smooth muscle cells and cardiac myocytes

Answer 104

VSMCs: - small - mononucleate - have gap junctions - smooth because myofilaments not in sarcomeres - not troponin or tropomyosin - don't need Ca release from SR for VSMCs - slower rate of contraction but more sustained - thick filament regulation - both have SERCA and PLB

Question 105

Describe the molecular steps involved in Ca regulation of vascular smooth muscle contraction

Answer 105

- doesn't need AP; can be done by stretching via myogenic response - Ca enters from SR or Ca channels --> Ca binds to calmodulin --> Ca-CaM binds to myosin light chain kinase and activates it --> MLCK phos/activates myosin head --> cross bridge - cAMP activates PKA which phos myosin to INHIBIT its activity --> relaxation

Question 106

Describe the mechanism by which sympathetic stimulation (via alpha1 adrenergic receptors) alters vascular tone

Answer 106

- symp stim --> vasoconstriction - alpha1 receptors are GPCRs (Gq) that activate PLC --> activate IP3 --> release Ca from SR --> contraction - also activate PKC that phos LTCCs --> activates more Ca release (CICR)

Question 107

Describe the arterial baroreceptor reflex arc

Answer 107

- baroreceptors are pressure-sensitive neurons in aortic arch and carotid sinus - respond to stretch (high BP) by increasing firing rate conferred by Na channels that are mechanosensitive (stretch causes Na channels to open and send APs) - neurons project to brainstem which then output symp and para fibers to the heart and symp fibers to vasculature - if inc fire rate --> dec symp and inc para output

Question 108

Name four tissue metabolites and the mechanisms by which they control local flow to a capillary bed

Answer 108

1) decreased PO2 - chemoreceptors in aortic/carotid bodies - low PO2 --> inc symp output 2) increased PCO2/decreased pH - same as above - high PCO2 --> inc symp output 3) increased K - K leaves cell in active skeletal muscle - Na/K pump can't keep up so K accumulates in interstitial space 4) increased adenosine - produced by hydrolysis of ATP - adenosine binds to A2 purinergic receptors --> GPCRs (Gs) --> inc cAMP --> vasodilation by PKA inhibiting MLCK

Question 109

Describe the myogenic response

Answer 109

- feedback mechanism to maintain constant flow when you have changes in pressure (when too low, inc; when too high, dec) - stretch --> VSMC contraction by opening stretch-activated Trp channels --> Ca comes in and causes vasoconstriction

Question 110

Describe how NO and endothelin regulate vascular smooth muscle tone

Answer 110

NO: - NO is a potent vasodilator - ACh activates GPCRs on endothelial membrane --> ER releases Ca and binds to CaM --> activates NOS --> makes NO --> diffuses to smooth muscle cell and activates guanylate cyclase --> produces cGMP --> activates PKG --> PKG activates SERCA and inhibits LTCCs--> dec Ca --> dec contraction --> vasodilation via dec MLCK activity Endothelin: - potent vasoconstrictor - endothelin from endothelium binds to ET receptors (GPCRs on VSMCs) --> Gq so inc Ca --> vasoconstriction

Question 111

Describe the renin-angiotensin-aldosterone system and how it regulates BP

Answer 111

- long term BP control - renin released into circulation by kidney when symp stim, dec BP in renal artery, or dec Na reabsorption in kidney - renin cleaves angiotensinogen to angiotensin I --> cleaved by ACE to angiotensin II --> potent vasoconstrictor via bindings to GPCRs on VSMCs - angiotensin II also stim symp, stim aldosterone release from adrenal cortex (promotes reabsorption of Na and H2O), stim release of endothelin, and stim release of ADH from pituitary (inc H2O reabsorption and vasoconstricts)

Question 112

Describe the origin and effects of atrial natriuretic peptide on BP

Answer 112

- ANP is a peptide release by atria that vasodilates - excretes sodium - secretion stimulatied by mechanical stretch of atria - ANP acts on natriuretic peptide receptors (guanylate cyclases) that produce cGMP --> actvate SERCA --> dec Ca --> dec vasoconstriction - ANP inc glomerular filtration rate and inc secretion of Na and H2O - ANP vasodilates (longer lasting than NO) - ANP inhibits release of aldosterone and renin

Question 113

Describe how G protein coupled receptors work

Answer 113

- ligand binding --> intracellular signaling - agonist binds receptor, GTP replaces GDP on alpha subunit, dissociate alpha and beta/gamma subunits, each can be signals - deactivated when GTP dephos to GDP, alpha combines with beta and gamma

Question 114

Describe Gs, Gi, and Gq GPCRs

Answer 114

- Gs: stimulatory for cAMP production by adenylate cyclase - Gi: inhibitory for cAMP production by adenylate cyclase - Gq: activation inc intracellular Ca via phospholipase C and PKC

Question 115

Describe parasympathetic regulation of inotropy

Answer 115

There is very little parasympathetic control/innervation of ventricles

Question 116

Map the sequence of major events between the initiation of an action potential in a cardiac muscle fiber, through contraction

Answer 116

- AP spreads into T-system - Ca channel in T-membrane opens an allows entry of extracellular Ca - this triggers the opening of RyR2 in the SR membrane - Ca ions leave SR lumen and enter myoplasm and bind troponin - actin-myosin cross-bridge cycling and contraction occurs

Question 117

Describe the processes that control relaxation of contraction by removing Ca from the myoplasm

Answer 117

1) SERCA2 pumps: - in longitudinal SR - 2 Ca per cycle - SR surrounds myofibrils, so SERCA is dominant - Vm = 0 so requires less energy to transport Ca across 2) NCX: - in junctional domains of plasma membrane and T-tubules - 3 Na in/1 Ca out 3) PMCA - extrudes Ca and uses ATP

Question 118

Compare and contrast EC coupling in skeletal and cardiac muscle

Answer 118

- both are elicited by an increase in myoplasmic Ca conc --> binding Ca to troponin allows actin-myosin interaction - both have SR as chief source of Ca that causes contraction - both have release of Ca originating between terminal cisternae of SR and plasma membrane/T-tubule - cardiac REQUIRES external Ca - skeletal DOES NOT REQUIRE external Ca - cardiac is Cav1.2 and RyR2 - skeletal is Cav1.1 and RyR1

Question 119

Describe how the exchange of 1 Ca for 3 Na ions, together with membrane potential and the Na and Ca gradients, governs the direction of Na and Ca movements via NCX

Answer 119

- the Vr where transport reverse directions is figured out by: Vr=3ENa-2ECa - the Nernst potential gets bigger if the outside conc is bigger - at rest, Vr = -74mV --> Ca leaves until Cai = 100nm - but if Nai were to increase (maybe from Na/K pump blocker) (decreased ENa and making Vr even more negative) then Cai increases to maintain Vr - during depol, Ca enters cell and Na exits - during repol, Cai increases due to SR release and you switch direction and Ca exits while Na enters

Question 120

Explain why the extrusion of Ca from the cytoplasm via NCX can cause membrane depolarization

Answer 120

- if Cai were to suddenly increase (like it does in SA nodal cells in an oscillatory manner being released from the SR) then the NCX would pump out Ca and bring Na in, so there would be an inward current; this inward current causes the cell to depol

Question 121

Identify basic elements of calcium homeostasis in the myocardium

Answer 121

- NCX - LTCC inactivation through Ca-dep inactivation (CDI) - CDI depends on Ca through LTCCs and through RyR2 - if Ca via RyR2 in SR inc, then CDI inc and less Ca through LTCC - if Ca via RyR2 in SR dec, then CDI dec and more Ca through LTCC

Question 122

Explain how stimulation of beta-adrenergic receptors increase both contraction strength, and rate of relaxation, of cardiac muscle

Answer 122

- beta adrenergic GPCR stimulated --> produce cAMP --> activates PKA --> 1) phosphorylates LTCC to increase Ca current --> increases trigger of RyR2 --> inc Ca released and --> inc inotropy/more contraction 2) phosphorylates RyR2 so that it is more sensitive to trigger Ca --> more CICR for less trigger --> inc inotropy and more contraction 3) phosphorylates PLB to prevent inhibition of SERCA so more Ca reuptake into SR --> inc lusitropy and more Ca load in SR so inc inotropy 4) phosphorylates troponin to make less sensitive to Ca which speeds rate of Ca dissociation --> inc lusitropy

Question 123

Describe why Timothy syndrome mutations of the LTCC could result in a lengthened cardiac AP and why Brugada syndrome mutations of the LTCC could result in shortened APs

Answer 123

Timothy Syndrome: - de novo mutations in Cav1.2 (LTCCs) - supresses voltage-dep inactivation - AV block and long QT intervals due to prolonged ventricular AP (Ca channel stays open longer since inactivation is suppressed) Brugada: - mutations of Na channel, IKto channel, Ca channel, LTCC, etc. - large reduction in magnitude of LTCC current - short QT interval --> weaker LTCC --> shorter AP

Question 124

Identify the mechanism whereby CPVT mutations, in combination with activation of beta adrenergic receptors, causes ectopic depolarizations

Answer 124

CPVT (catecholaminergic polymorphic ventricular tachycardia): - ECG abnormalities with exercise or catecholamines - mutations in RyR2 --> leak of Ca out of SR/make RyR2 more sensitive to activation by Ca - beta adrenergic receptors increase SR Ca content + CPVT mutation --> release of Ca that is not triggered by LTCC during phase 2 of AP but instead after repol --> this Ca is extruded by NCX --> Na comes in and depolarizes cell --> ectopic APs --> arrhythmias

Question 125

What is the hallmark of systolic heart failure?

Answer 125

- HFrEF - LVSD - ventricular enlargement --> dilated cardiomyopathy

Question 126

What are causes of systolic heart failure?

Answer 126

- destruction of heart muscle cells (MI) - overstressed heart muscle (tachycardia) - volume overloaded heart muscle (mitral regurg, high CO)

Question 127

What change in the PV loop do you see in systolic heart failure?

Answer 127

- starling curve shifts down (lose inotropy) - dec SV due to inc ESV - lower systolic BP

Question 128

What is the hallmark of diastolic heart failure?

Answer 128

- HFpEF | - ventricular wall thickening: LVH or HCM

Question 129

What are the causes of diastolic heart failure?

Answer 129

- high afterload (HT, aortic stenosis) - myocardial thickening/fibrosis (HCM) - external compression (pericardial effusion)

Question 130

What does the PV loop look like in diastolic heart failure?

Answer 130

- EDV curve shifts up (for a given preload/EDV, more pressure needed because heart is stiffer) - decreased SV because EDV is decreased

Question 131

What are the effects of right heart failure?

Answer 131

- dec circulating blood flow (forward RV HF) | - inc venous pressure (backward RB HF)

Question 132

What are the causes of right heart failure?

Answer 132

- left heart failure (backward HF form LV leads to back up into lungs and RH has to work harder to push against that) - lung disease (cor pulmonale) - RV volume overload (tricuspid regurg) - damage to RV myocardium

Question 133

Describe how the sympathetic and parasympathetic divisions of the autonomic nervous system function to maintain a stable internal environment within a narrow physiological range

Answer 133

- two-neuron system: pregang neuron from CNS to autonomic ganglia containing postgang neuron to target Sympathetic: - pregang neurons from thoracic and lumbar spine to innervate postgang axons using ACh - postgang neurons release NE and are in ganglia of sympathetic trunk and travel to sweat glands, blood vessels, hair follicles, etc. - symp controls vasodilation and vasoconstriction and also increases HR and force of contraction Parasympathetic: - pregang from brainstem and sacral spine - cranial nerves (3, 7, 9, 10) - ACh as neurotransmitters - innervate colon, rectum, bladder, genital organs - decrease HR and force of contraction

Question 134

Describe how the ANS maintains homeostasis to the control of blood pressure

Answer 134

- symp stim: increase BP through inc in HR and contractile force and vasoconstriction - para stim: decrease BP through dec in HR and contractile force

Question 135

Describe the role of the hypothalamus in regulating the CV system via the ANS and posterior pituitary

Answer 135

- hypothalamus considered head ganglion of ANS because it integrates info from several regions to the pregang neurons in CNS - hypothalamus controls release of hormones via pituitary - low BP detected --> release of vasopressin in post pituitary --> vasoconstriction --> kidneys increase H2O retention

Question 136

Describe the actions of sympathomimetic and parasympathomimetic drugs on heart function

Answer 136

- mimic sympathetic and parasympathetic activity

Question 137

How does the adrenal medulla play a role in sympathetic nervous system?

Answer 137

- neuroendocrine gland | - postgang neurons in adrenal medulla secrete epinephrine and NE which bind to adrenergic receptors in blood stream

Question 138

Describe the different receptor subtypes for ACh

Answer 138

- nicotinic: present in cell body of postgang neurons - ligand-gated, non-selective cation channel - ACh binds and channel opens allowing Na and K to cross membrane --> depol and excitation - muscarinic: present on effector cells of cardiac and smooth muscle and glands - linked to G protein - ACh binds --> G protein activated --> G protein activates or inhibits other stuff - in atrium, ACh from vagus nerve binds and activates G protein then opens K channels --> hyperpol and slowing down of heart

Question 139

Describe the different receptor subtypes for NE

Answer 139

- alpha and beta receptors - NE only activates alpha1, alpha2, and beta1 - epinephrine activates those 3 and beta2

Question 140

Describe the mechanism of NE sympathetic on an SA node cell

Answer 140

NE binds to beta1 receptor --> G protein activated --> activates adenylate cyclase --> produces cAMP --> opens Ca channel and HCN --> influx of Ca and If - higher amplitude - faster upstroke - inc rate - inc force - inc rate of depol during diastole

Question 141

Describe the effect of ACh on an SA node cell

Answer 141

ACh binds to M2 receptor --> activates G protein --> dec activity of adenylate cyclase --> decrease production of cAMP --> close Ca channels and open K channels to allow for repol - dec rate - dec force - dec amplitude - slower upstroke - dec rate of depol during diastole

Question 142

Describe the baroreceptor reflex parasympathetic and sympathetic activity

Answer 142

Parasympathetic: - inc BP --> inc stretch --> vagus nerve transmits signal to NTS in medulla --> activates glutamatergic neurons --> inc glutamate --> release ACh on ganglia through pregang neuron --> postgang neuron release ACh onto SA node cells --> dec HR Sympathetic: - vagus nerve --> activates glutamatergic neurons --> release GABA --> GABA inhibits release of glutamate in thoracic spine --> decreased release of aCh from pregang to postgang --> postgang decreased release of NE onto SA nodal cells

Question 143

Recognize the major symptoms associated with heart failure, particularly those related to decreased CO, increased pulmonary venous pressure, and increased central venous pressure

Answer 143

dec CO: - dec muscle perfusion (fatigue) - decreased gut perfusion (anorexia) - decreased kidney perfusion (dec urine; renal dysfunction) - exercise intolerance (can't inc CO to meet stress) inc pulm venous pressure: - dyspnea (on exertion) - orthopnea (SOB when flat since more blood back in circulation) - pulm edema inc central venous pressure: - edema

Question 144

Be acquainted with the functional classification schemes for heart failure

Answer 144

Asymptomatic --> Symptomatic w/ moderate exertion --> Symptomatic w/ minimal exertion --> Symptomatic at rest

Question 145

Identify the common precipitants of worsening heart failure symptoms, and the variable clinical course of heart failure

Answer 145

inc circulating volume (preload): - Na in diet - renal failure inc pressure (afterload) - HT - aortic stenosis - PE dec inotropy - myocardial ischemia - beta blocker or Ca channel blocker arrhythmia - bradycardia - afib inc metabolic demands - fever, infection, etc. not taking HF meds

Question 146

Identify the key physical signs of heart failure, and how they relate to the underlying pathophysiology

Answer 146

Low flow - cool extremities due to peripheral vasoconstriction - tachycardia to compensate for low SV - low pulse pressure (can't create a large systolic output so not a big difference between diastolic and systolic) Left-sided filling (pulmonary venous pressure) - rales - tachypnea Right-sided filling (systemic venous pressure) - edema - hepatosplenomegaly - JVD a and v waves Gallops - S1: mitral/tricuspid close - S2: aotic/pulmonary close - S3: rapid expansion of ventricle walls in early diastole --> indicates HFrEF - S4: atria contracting forcefully to overcome stiff LV

Question 147

Describe the primary laboratory tests and imaging studies that are most helpful in making a diagnosis of heart failure, including natriuretic peptides, cardiac imaging studies (how to assess LVEF), and hemodynamics obtained from a pulmonary artery catheter

Answer 147

- chest x-ray (large heart in HFrEF, pulm edema) - natriuretic peptides (BNP secreted in response to ventricular stretch) - ecg (not directly HF but other findings) - cardiac imaging (measure EF) - echo - right heart catheter (can measure post capillary wedge pressure = left atrial pressure)

Question 148

Discuss the major significance of heart failure in the US

Answer 148

- common, chronic health care problem that affects survival, quality of life, and health care costs - median age of patients with HF is 75

Question 149

Recognize the physiology explains the pathophysiology

Answer 149

uh ok - function determines dysfunction -

Question 150

Define the syndrome of heart failure, and recognize that both a decrease in cardiac output and increase in filling pressures are fundamental to the pathophysiology

Answer 150

- heart failure is defined as the inability of the heart to pump blood forward at a sufficient rate to meet metabolic demands of the body (FORWARD FAILURE) - dec CO OR the ability to do so only if the cardiac filling pressures are abnormally high (BACKWARD FAILURE) - inc filling pressure/congestion (usually a response to dec CO)

Question 151

Describe the difference between systolic and diastolic dysfunction

Answer 151

Systolic HF: - problem with contraction (dec inotropy) - HFrEF - LVSD - DCM - caused by destruction of heart cells (MI), overstressed heart muscle (tachycardia), or volume overload (mitral regurg, high CO) Diastolic HF: - problem with filling (dec lusitropy) - HFpEF - LVH - HCM - caused by high afterload (HT), myocardial thickening (HCM), external compression (pericardial effusion)

Question 152

Describe compensatory responses to decreased cardiac output seen in heart failure, including neurohormonal activation of adrenergic and RAAS systems, Frank-Starling increases in preload, and ventricular remodeling via hypertrophy and dilation

Answer 152

Activation of adrenergic system: - vasoconstriction - tachycardia - inc inotropy - dec CO --> baroreceptor reflex --> adrenergic activation --> inc HR + vasoconstrict Activation of RAAS: - vasoconstriction - salt/H2O retention --> inc volume --> inc LV filling/preload Frank-Starling inc in preload: - F-S curve shifts down so to compensate, increase EDV to inc SV Ventricular remodeling - ??

Question 153

Recognize the major goals of therapy, including correction of any reversible causes, reduction of congestion, and optimization of cardiac function

Answer 153

Correct underlying cause of HF - revascularize if ischemia - many irreversible though Eliminate precipitating factors - infection, anemia Reduce congestion - fluid optimization Improve flow - med devices Modulate neurohormonal activation - positive remodeling

Question 154

Name the major classes of medications for heart failure, including diuretics, vasodilators, neurohormonal antagonists, and inotropes

Answer 154

Diuretics - reverse Na and fluid retention (pee off excess fluid) - really common in HF - IV inpatient because of poor bioavailability - right side of F-S curve so that big dec in EDV lead to small changes in SV so you can reduce congestion without affecting CO Vasodilators - arterial vasodilation/antihypertensives (dec afterload) - venous vasodilation (dec preload) - pulmonary artery vasodilation (dec RV afterload) Neurohormonal antagonists 1) ACE inhibitors (-pril) - block AT1-->AT2 - vasodilation - dec aldosterone activation (dec Na/H2O retention) - side effects: hypotension, dec renal function, hyperkalemia, cough 2) AT2 receptor blockers (-sartan) - similar effect to ACE inhibitors - side effects: no cough like with ACE inhibitors, but similar 3) Aldosterone receptor blockers - block effect of aldosterone on kidney --> dec Na/H2O retention - side effect: hyperkalemia 4) Beta-blockers (-olols) - block beta1 --> dec chronotropy and inotropy - block alpha 1 --> vasodilate - side effects: short term loss for long term gain (fluid retention, hypotension, dec CO) Inotropes - digoxin (K/Na exchanger), dobutamine (beta agonist) - short term to reverse shock - long term HF is worsened though

Question 155

Describe non-pharmacologic therapies for heart failure, including electrical therapies and advanced therapies

Answer 155

ICD - LVEF inc SV and dec regurgitation - usually with ICD Cardiac transplant Mechanical circulatory support Hospice

Question 156

Describe the non-linear clinical course of heart failure, and how different therapeutic approaches are used at different stages of the disease process

Answer 156

Acute: - IV diuretics - IV vasodilators - IV inotropes for shock - CPAP for hypoxia (can reduce preload) - cut back on beta-blockers in severe cases ??

Question 157

Recognize that most specific heart failure therapies are indicated for patients with HFrEF; for the approximately 50% of patients with heart failure and relatively normal ejection fraction HFnEF, treatment consists of diuretics and management of underlying causes

Answer 157

Improve symptoms: - diuretics - inotropes Prolong survival - ACE inhibitors - AT2 receptor blockers - beta blockers - aldosterone antagonists - vasodilators - CRT - ICD

Question 158

Recognize the importance of prevention and list specific prevention goals

Answer 158

- BP

Question 159

What is the mechanism of action, metabolism, side effects, drug-drug interactions, and monitoring parameters of ACE inhibitors/ARBs?

Answer 159

Mechanism of action: - ACE inhibitors block ACE and Kinase II which convert AT1 to AT2 and Bradykinin to Inactive Fragments respectively - bradykinin potent vasodilator and block of AT2/aldosterone production means dec vasoconstriction - ARBs block AT2 receptor so don't affect kinase II Drug-drug interactions (for ACE inhibitors): - Lithium - NSAIDs - diuretics Side effect: - bad cough, hyperkalemia, angioedema, - ARBs don't have cough but similar side effects Monitoring: - Chemistry-7, CBC, BP every month - for ARB, watch for overproducers of uric acid

Question 160

What is the mechanism of action, metabolism, side effects, drug-drug interactions, and monitoring parameters of neprilysin inhibitors?

Answer 160

- valsartan+neprilysin blocks AT2 receptor and blocks neprilysin breakdown of BNP - BNP made during HF - BNP causes vasodilation, dec fibrosis, dec BP, diureses - used in placed of an ACE inhibitor

Question 161

What is the mechanism of action, metabolism, side effects, drug-drug interactions, and monitoring parameters of ivabradine?

Answer 161

- affects chronotropy but not inotropy - closes HCN channel and delays If --> dec HR - bad for pregnant women - monitor for afib - can affect QT interval

Question 162

What is the mechanism of action, metabolism, side effects, drug-drug interactions, and monitoring parameters of beta blockers?

Answer 162

Mechanism: - NE produced by nerve - NE activates beta1 a lot (and beta2) --> GPCR --> inc cAMP --> inc PKA --> phos of a lot of stuff --> inc inotropy - beta-blockers are antagonists for these receptors - need to start low and up-titrate (gets worse before getting better) - initially dec CO and dec HR --> inc over time - shields from NE and have upreg of beta1 - 1st gen: propanolol - non-selective and block beta1 and beta2 (dec HR and inotropy) - 2nd gen: metroprolol - selective for beta1 and beta2 receptors (dec HR and inotropy) - 3rd gen: carvedilol - antagonist foe beta1, beta2, and alpha1 (vasodilatory)

Question 163

Describe the mechanism of action, metabolism, side effects/toxicity, drug-drug interactions, monitoring parameters for digoxin

Answer 163

- inc Ca intracellularly - binds Na/K pump --> Na accumulates in cell --> Na exchanged for Ca with NCX --> inc inotropy and chronotropy - renally excreted; so contraindicated in patients with renal dysfunction - toxicities: heart block, vomiting, headache, fatigue, arrhythmia, hypokalemia, - drug-drug: antiarrhythmics, azole antifungals, verapamil/diltiezam, macrolides, quinine

Question 164

Describe the mechanism of action, metabolism, side effects/toxicity, drug-drug interactions, monitoring parameters for dobutamine

Answer 164

- beta1 agonist --> inc inotropy - ADHF short term management - side effects: angina, tachyarrhythmia - recommended if hypotensive

Question 165

Describe the mechanism of action, metabolism, side effects/toxicity, drug-drug interactions, monitoring parameters for milrinone

Answer 165

- inhibits breakdown of cAMP via phosphodiesterases - ADHF short term management - recommended if receiving a beta blocker - side effects: hypotension, tachycardia, arrhythmia, fever

Question 166

Describe the mechanism of action, metabolism, side effects/toxicity, drug-drug interactions, monitoring parameters for dopamine

Answer 166

- endogenous precursor of NE --> directly stimulate adrenergric receptors

Question 167

Describe the presenting symptoms and signs of, diagnostic approaches to and treatment for acute pericarditis

Answer 167

Presentation: - caused by virus, CT or AI disease, uremia, metastatic tumors - presents with sudden onset of severe chest pain that varies with position Diagnosis: - chest pain that varies with position - pericardial rub on cardiac exam - diffuse ST elev - pericardial fluid - diagnosis of exclusion (presume MI, treat with angiplasty, if not better then consider pericarditis) - responds to NSAIDs Treatment: - ibuprofen 300-800mg po ever6-8hrs

Question 168

Describe the clinical manifestations, diagnosis and treatment of constrictive pericarditis

Answer 168

Presentation: - scarring and loss of elasticity of pericardium - constrains how much can expand during diastole but normal systole--> inc diastolic pressure --> right sided HF - idiopathic, after cardiac surgery, radiation, infection - inc JVP, tachycardia, hepatomegaly, edema, ascites - resembles restrictive cardiomyopathy - takes long time to develop - lungs not congested because impaired filling of RV - often mistaken for liver disease because prolonged high venous pressure causes hepatomegaly and ascites - dip and plateau during diastole and equalization of diastolic pressures between RV and LV Diagnosis: - echo or xray for thickened or calcified pericardium Treatment: - surgical stripping of pericardium

Question 169

Outline the clinical manifestations, diagnosis and treatment of pericardial effusion

Answer 169

Presentation: - causes: viral or acute idiopathic, metastatic malignancy, uremia, AI disease, hypothyroidism Diagnosis: - xray or echo - look for an enlarged heart and non-congested lung fields (bc RV filling is impaired so lungs are not congested) - inspiration --> inc filling of RV but dec LV --> dec SV - ECG shows electrical alternans Treatment: - can drain if large effusions with high intrapericardial pressures - small effusions may be asymptomatic and may not need drainage

Question 170

Outline the clinical manifestations, diagnosis and treatment of cardiac tamponade

Answer 170

Presentation: - caused by large pericardial effusion - presents with same signs as pericardial effusion - dec RV diastolic filling during inspiration - distended neck veins - inspiratory dec in arterial pressure Diagnosis: - ECG shows low voltage with sinus tachycardia and electrical alternans with sinus tachycardia - echo shows collapse of RA and RV in end-diastole and dilation of IVC Treatment: - pericardiocentesis

Question 171

Describe the EKG changes produced by ventricular hypertrophy

Answer 171

- more muscle mass = greater amplitude - LV hypertrophy --> big R waves in leads I, aVL, V5, and V6 - RV hypertrophy --> big R waves in V1 and V2

Question 172

Describe the EKG changes produced by myocardial ischemia

Answer 172

- with sudden high O2 demand --> ST depression - acute clot in coronary artery --> T wave inversion - transmural injury --> ST elevation

Question 173

Describe the EKG changes produced by myocardiac injury or infarction

Answer 173

- four stages of evolving transmural MI 1) Peaked T wave (usually only a few minutes and rarely actually see) 2) T-wave inversion 3) ST elevation 4) Q-waves, ST elev, T inversion

Question 174

Describe the EKG changes produced by electrolyte disorders

Answer 174

Hypercalcemia - shortened QT Hypocalcemia - prolonged QT Hypokalemia - due to vomiting, diarrhea, or diuretics - prolonged QT - U waves - inverted T waves Hyperkalemia - mild: T wave elevated - high: P flat, wide QRS and T, wider S - higher: no P or R, sinusoid

Question 175

Describe the important parts of a normal EKG

Answer 175

- P wave = atrial depol - QRS = ventricular depol (normal: .06-.1sec) - T wave = ventricular repol - PR interval = time for depol to travel from atria to ventricle (normal: .12-.2sec) - QT interval: total duration of depol and repol - depol moving towards positive electrode --> positive deflection (QRS up in left and lateral leads, down in right side leads) - 12 leads: limb leads I, II, III, augmented limb leads aVL, aVR, aVF, precordial leads V1-V6 - thin lines are .04sec apart - thick lines are .2sec apart

Question 176

How do you find the HR on an ECG?

Answer 176

HR = 300/#of heavy lines between two waveform = 1500/#of small lines between 2 waveforms

Question 177

What difference in ECGs do transmural infarcts show vs. subendocardial infarcts?

Answer 177

- transmural: ST elevation with Q waves | - subendocardial St depression with no Q waves

Question 178

What are the causes, EKG findings, and treatments for sinus tachycardia?

Answer 178

Causes: - exercise - emotion - hypotension EKG findings: - normal waves with increased frequency Treatment: - none - beta blockers

Question 179

What are the causes, EKG findings, and treatments for sinus bradycardia?

Answer 179

Causes: - athletes - may produce fatigue or syncope - sick sinus syndrome EKG findings: - normal waves with decreased frequency Treatment: - none - atropine or pacemaker

Question 180

What are the causes, EKG findings, and treatments for AV block?

Answer 180

Causes: - 1st deg: drugs (beta blockers, Ca blockers, digitalis), conduction system disease - 2nd deg: conduction disease, high vagal/para tone, excess effect of drugs - 3rd deg: AV node/junctional failure, disruption during surgery EKG findings: - 1st deg: PR >.2 sec - 2nd deg: Mobitz 1 - PR lengthens until P doesn't conduct, Mobitz 2 - no change in PR, just some P waves don't conduct - 3rd deg: P waves and QRS waves are at different rhythms (P faster than QRS) Treatment: - 3rd deg: acute - temporary pacemaker, chronic - permanent

Question 181

What are the causes, EKG findings, and treatments for atrial flutter?

Answer 181

Causes: - clot may form in left atrium --> embolic stroke EKG findings: - P waves 240-320bpm - multiple P waves per QRS Treatment: - treat with anticoag (warfarin), rate control (beta blockers), cardioversion, ablation

Question 182

What are the causes, EKG findings, and treatments for atrial tachycardia?

Answer 182

Causes: - usually due to reentry EKG findings: - rapid HR (~180bpm) - narrow QRS - P waves present but abnormal Treatment: - adenosine - ablate reentry pathway

Question 183

What are the causes, EKG findings, and treatments for junctional rhythm?

Answer 183

Causes: - rhythms originate from area surrounding the AV node (the junction) EKG findings: - narrow QRS - no P wave because buried within QRS - if P wave, then inverted Treatment: - none

Question 184

What are the causes, EKG findings, and treatments for premature contractions?

Answer 184

Causes: - common as single beat palpitations EKG findings: - APC: abnormal P wave preceding, narrow QRS - VPC: no P wave, wide QRS Treatment: - if a lot, then beta blockers

Question 185

What are the causes, EKG findings, and treatments for ventricular tachycardia?

Answer 185

Causes: - can lead to death EKG findings: - wide abnormal QRS Treatment: - amiodarone - lidocaine - cardioversion

Question 186

What are the causes, EKG findings, and treatments for ventricular fibrillation?

Answer 186

Causes: - requires emergency defib EKG findings: - varying, wide QRS - squiggly lines - loss of PQRST waveform Treatment: - emergency defib - ICD and meds

Question 187

What is the algorithm for identifying common cardiac rhythms?

Answer 187

1) is there a P followed by a QRS? 2) is AV block present? 3) are occasional early QRS present? 4) are fast abnormal P waves present? 5) are no P waves present but QRS present? 6) are no P waves and no QRS present?

Question 188

What are the causes, EKG findings, and treatments for atrial fibrillation?

Answer 188

Causes: - aging, post-op, heart disease, hyperthyroidism, *dilation or fibrosis of atria - rapid HR - loss of atrial kick (lose 20% of filling) - atrial thrombi EKG findings: - irregularly irregular - no P waves - irregular QRS waves - chaotic atrial Treatment: - anticoag - beta blockers, Ca channel blockers - cardioversion - ablation

Question 189

Treatment for bradyarrhythmias

Answer 189

- find/treat reversible causes (ischemia/infarction, hypothyroidism, etc.) - stop offending meds (beta blockers, Ca channel blockers, antiarrhythmic drugs) - acute stabilization: beta agonist, pacing, - long term pacemaker

Question 190

What is MAT?

Answer 190

Multifocal atrial tachycardia | - 3+ P wave morphologies

Question 191

What are the irregular supraventricular tachyarrhythmias and how do you generally treat them?

Answer 191

- Afib - MAT - Aflutter - if unstable --> shock - treat with rate control, antiarrhythmics, or cardioversion

Question 192

How do you treat Afib?

Answer 192

5 Cs: - reverse Cause (hyperthyroidism, alcohol, mitral valve disease, infection, PE) - Control rate - antiCoagulate - Control rhythm (cardioversion) - Cure with ablation but less likely than aflutter

Question 193

What are the regular supraventricular tachyarrhythmias and how do you generally treat them?

Answer 193

- Sinus tach - AVNRT - AVRT - AFL - AT - JT - treat with adenosine - then vagal maneuvers, meds only w/ symptoms, betablockers, Ca blockers - catheter ablation --> 90% cure

Question 194

How do you treat ventricular tachycardia?

Answer 194

Stable: - amiodarone - lidocaine - procainamide - treat underlying causes Unstable: - SHOCK - treat underlying causes - meds With structural heart disease: - treat underlying causes Without structural heart disease - rarely defib

Question 195

How can adenosine be used to diagnose regular SVTs?

Answer 195

add adenosine - if ST --> complete heart block, sinus Ps, ST - if AVNRT --> terminate - if AVRT --> terminate - if AFL --> CHB, flutter waves, AFL - if AT --> CHB, ectopic Ps, AT or terminate - if JT --> nothing or terminate

Question 196

Describe the site and mechanism of action at the nephron, role in the treatment of heart failure, adverse effects - especially as it relates to effects on plasma electrolytes, and loop (high ceiling) of furosemide

Answer 196

Mechanism at nephron: - normally, ascending limb reabsorbs Na/K/2Cl into ascending limb but no H2O - furosemide blocks this transporter, so Na leaves in urine - inc in Mg and Ca excretion - inc renal flow through RAAS Role in treating HF: - used with treating volume overload - treats acute pulm edema and hypercalcemia - HF patients have reduced diuretic response because decreased RBF Adverse effects: - hypokalemic metabolic acidosis (asecrete K) - ototoxicity - hyperuricemia/hyperglycemia - hypomagnesemia - overdose --> rapid BP drop --> dizziness, orthostatic hypotension High ceiling:

Question 197

Describe the site and mechanism of action at the nephron, role in the treatment of heart failure, adverse effects - especially as it relates to effects on plasma electrolytes, and loop (high ceiling) of thiazides

Answer 197

Mechanism at nephron: - normally, NaCl reabs occurs via Na/Cl transporter - thiazides inhibit the Na/Cl cotransporter --> inc excretion of NaCl - also a Na/Ca transporter on basolateral side that pumps out Na and brings in Ca --> inc reabs of Ca with dec intracellularNa Role in treating HF: - supplements effect of furosemide - helps mild hypertension - helps hypercalcuria --> decreasing excretion of Ca decreases incidence of kidney stones Adverse effects: - competition with uric acid secretion --> gout - hypokalemia - 2ndary hyperaldosteronism - hyperglycemia/glucosuria - hyperlipidemia - allergies High ceiling:

Question 198

Describe the site and mechanism of action at the nephron, role in the treatment of heart failure, adverse effects - especially as it relates to effects on plasma electrolytes, and loop (high ceiling) of aldosterone antagonists

Answer 198

Mechanism at nephron: - aldosterone inc number and activity of Na and K channels and Na/K ATPase --> inc reabs of Na - blocking aldosterone receptor dec Na reabs and dec K excretion Role in treating HF: - anti-remodeling --> dec hypertropy and fibrosis - K-sparing (helps with loop diuretics and etc.) - treat hypertension Adverse effects: - hyperkalemia - endocrine abnormalities (gynecomastia) with spironolactone via block of androgen receptor High ceiling:

Question 199

Describe the site and mechanism of action at the nephron, role in the treatment of heart failure, adverse effects - especially as it relates to effects on plasma electrolytes, and loop (high ceiling) of Na channel blockers

Answer 199

Mechanism at nephron: - at collecting tubules, Na reabs and K excreted - Na channel blocker dec Na reabs Role in treating HF: - Adverse effects: High ceiling:

Question 200

Describe renin-angiotensin-aldosterone system (RAAS) and the contribution of chronic RAAS activation to the underlying pathology of heart failure

Answer 200

- when low blood flow to kidneys --> kidneys produce renin --> renin converts angiotensinogen to angiotensin1 --> ACE converts AT1 to AT2 --> AT2 leads to vasoconstriction and the production/secretion of aldosterone --> inc TPR and Na/H2O retention --> inc BP --> inc venous return --> inc preload --> inc SV --> inc CO

Question 201

Describe the target and mode of action, role in the treatment of heart failure, adverse effects - especially in relation to serum potassium and renal function, and interactions with other drugs used in heart failure of ACE inhibitors

Answer 201

Mechanism: - inhibits conversion of AT1 to AT2 --> dec vasoconstriction and excess prod of aldosterone - dec preload and afterload - dec remodeling due to aldosterone Role in treating HF: - moderates remodeling - dec preload and afterload Adverse effects: - cough - angioedema - hyperkalemia - contraind in pregnancy Drug drug interactions:

Question 202

Describe their target and mode of action, role in the treatment of heart failure, adverse effects - especially in relation to serum potassium and renal function, and interactions with other drugs used in heart failure of ARBs

Answer 202

Mechanism: - inhibit AT2 receptor AT_1 - prevents remodeling and reduces sympathetic activity - no cough or angioedema like ACEis and there are other pathways to form AT2 besides ACE - loss of bradykinin vasodilation like in ACEi - doesn't take into account AT_2 receptor Role in treating HF: - similar to ACEi --> dec vasoconstriction and dec Na/H2O retention Adverse effects: - contraindicated in pregnancy - similar to ACEi - no cough or angioedema Drug drug interactions:

Question 203

Describe the lead systems of the 12 lead ECG and the planes and the regions monitored by the individual leads

Answer 203

- 3 limb leads: I, II, III - 3 augmented lim leads: aVR, aVF, aVL - 6 precordial leads: V1-V6 - lateral leads: aVL and I - inferior leads: II, III, and aVF - frontal plane: limb and augmented limb leads - horizontal plane: precordial leads

Question 204

Explain how to determine the frontal plane QRS axis

Answer 204

- normal: QRS is positive in I and II - left axis: positive in I and negative in II - right axis: negative in I and positive in II - indeterminate: negative in I and II

Question 205

Where are P wave abnormalities best seen?

Answer 205

Lead II (and V1) - in II, RA and LA are positive and combine to make a symmetric hump normally - in V1, RA is positive and LA is negative so have a small sinusoid - if RA is enlarged, see a more pronounced left side - if LA is enlarged, see a more pronounce right side

Question 206

Describe the ECG findings in right and left bundle branch block

Answer 206

RBBB: - wide QRS are most often RBBB - positive QRS and negative T-wave in right sided leads because delayed conduction to right side, so RV depol is not overshadowed by LV depol - negative QRS in left leads due to delay LBBB: - delayed left conduction - wide QRS away from V1 towards V6 - negative QRS in right sided leads and positive QRS in left sided leads

Question 207

What are the signs of left anterior hemiblock and left posterior hemiblock

Answer 207

- normal (not wide) QRS - if I and II are positive --> normal - if I positive and II negative (and III negative) then LAD and have LAH - if I negative and II positive (and III positive ) then RAD and have LPH

Question 208

Distinguish right and left ventricular hypertrophy on the ECG

Answer 208

RVH: - large R waves in V1 and V2 LVH: - add neg peak in V1 (S wave) to peak of V5/V6; if >40 then LVH - or just have really high QRS in V5 and V6

Question 209

Identify the ECG findings in acute coronary syndromes and pericarditis

Answer 209

- pericarditis has diffuse ST elevation - MI has ST elevation in specific regions - ischemia has ST depression on high O2 demand - subendocardial ST depression with no Q wave - transmural infarct ST elevation and Q wave - T inversion --> ischemia or hypertrophy or RBBB - Q waves in at least 2 adjacent leads --> transmural necrosis - long QT --> electrolyte imbalance

Question 210

Describe aortic and pulmonic valve anatomy and function

Answer 210

Aortic valve: - between LV and rest of body - prevents backflow from body back into LV Pulmonic valve - between RV and pulmonary artery - prevents backflow from lungs/pulmonary artery into RV

Question 211

Describe the cause, presentation/PE findings, and treatment for aortic stenosis

Answer 211

Cause: - aortic valve was many annuli - rheumatic (calcified - calcific aortic stenosis - bicuspid (congenital) Presentation: - dec AV opening during systole --> LV outflow obstruction - inc in LV pressure to overcome narrowing of AV - dyspnea on exertion - exertional syncope or lightheadedness - exertional angina - harsh, cresc-decres systolic murmur over right upper sternal border - worse if mid to late peaking murmur or if S2 is soft or if slow rate in rise of carotid pulse Treatment: - treat as soon as you see symptoms - monitor/check with PE, echo, and cardiac catheterization - drugs are complicated (diuretics dec preload, but with AS, kind of want preload)

Question 212

Describe the cause, presentation/PE findings, and treatment for bicuspid aortic stenosis

Answer 212

Cause: - cusp fusion in development with loss of elastic fibers - altered matrix structure (smooth muscle detachment, MMPs, loss of structure and elasticity) - AD inheritance Presentation: - aortic stenosis - aortic insuff - endocarditis - aortic dilation - aortic aneurysm - aortic dissection - similar to calcific stenosis (angina, syncope, SOB) - LVH - systolic ejection murmur - doming during systole Treatment: - monitor via echo - aortic valve replacement - screen 1st deg family members

Question 213

Describe the cause, presentation/PE findings, and treatment for calcific aortic stenosis

Answer 213

Cause: - similar risk factors as atherosclerosis - displacement of elastic lamina - Presentation: - angina, syncope, SOB - systolic ejection murmur - narrow split in S2 Treatment: - check with echo - AV replacement

Question 214

Describe the cause, presentation/PE findings, and treatment for aortic regurgitation

Answer 214

Cause: - aortic valve disease (rheumatic, endocarditis, degenerative, congenital) - aorta disease (dissection, atherosclerosis, marfan's, syphilis) - insufficient valve closure so that blood flows backwards into LV from aorta during diastole - aortic root dilation and bicuspid aortic valve and rheumatic disease Presentation: - austin-flint (high pitched) murmur - rapid/forceful carotid pulse - diastolic blanching of nail bed - bobbing head - LV dilation and dysfunction - dyspnea, pulm edema, orthopnea - longer diastolic murmur --> more severe Treatment: - AV replacement

Question 215

Describe the cause, presentation/PE findings, and treatment for pulmonic stenosis

Answer 215

Cause: - congenital Presentation: - PS --> RVH --> RV enlargement and failure - exertional dyspnea, angina, syncope - peripheral edema - systolic ejection murmur at left upper sternal border Treatment: - balloon valvuloplasty

Question 216

Describe the cause, presentation/PE findings, and treatment for pulmonic insufficiency

Answer 216

Cause: - infection, rheumatic, carcinoid, congenital - pulm artery dilation, pulm hypertension Presentation: - RV volume overload - RV dysfunction - atrial and ventricular arrhythmias - early diastolic murmur over 2nd and 3rd left intercostal spaces - may inc in intensity with inspiration - systolic ejection murmur at left upper sternal border due to inc RV SV Treatment: - if asymptomatic, then fine

Question 217

Describe the cause, presentation/PE findings, and treatment for mitral stenosis

Answer 217

Cause: - rheumatic fever - strep infection cross reaction - calcified commissures - often with mitral regurg Presentation: - loud S1 and S2 with opening snap after S2 and diastolic rumble - systolic murmur with mitral regurg - inc pressure in LA, lungs, right heart - dyspnea - hemoptysis - pulm hypertension - right sided HF (edema, ascites) - afib - stroke - EKG shows LAE, RVH if pulm hypertension, maybe afib - echo shows restricted opening of MV during diastole Treatment: - balloon valvuloplasty - beta blockers to slow HR - MV replacement

Question 218

Describe the cause, presentation/PE findings, and treatment for mitral regurgitation

Answer 218

Cause: - MV doesn't close so blood flows backwards from LV to LA during systole - myxomatous --> mitral valve prolapse - endocarditis - cardiomyopathy, myocarditis Presentation: - holosystolic murmur at apex radiating to axilla - CHF symptoms - mitral prolapse (mid systolic click and late systolic murmur) Treatment: - diuretics for CHF - afterload dec (ACEi, ARBs) - mitral valve repair/replacement

Question 219

Describe the cause, presentation/PE findings, and treatment for tricuspid insufficiency

Answer 219

Cause: - functional (2ndary to annular dilation and leaflet tethering in RV dilation from volume overload) - rheumatic disease, endocarditis, Presentation: - JV distension with v wave - hepatomegaly - holosystolic murmur of tricuspid regurg along sternal border inc with inspiration - fatigue - edema - dyspnea Treatment: - treat underlying causes of RV pressure/overload - diuretics - tricuspid repair/replacement

Question 220

Describe the cause, presentation/PE findings, and treatment for tricuspid stenosis

Answer 220

Cause: - rare - rheumatic heart disease - congenital - RA tumors Presentation: - dyspnea - edema - often with mitral stenosis Treatment: - diuretics - surgery

Question 221

Describe common cardiac symptoms and conditions

Answer 221

- SOB at rest or with exertion - irregular heart beat - faintness of dizziness - swelling in feet or hands - awaking from sleep with SOB - difficulty sleeping when flat - leg pain with activity - stroke - chest pain/pressure - passing out - blue lips/digits

Question 222

Describe chest pain due to cardiac ischemia also known as angina pectoris

Answer 222

causes: - cardiac - CAD, AV disease, pulm hypertension, MV prolapse, pericarditis - vascular - aortic dissection - pulm - pulm embolism, pneumonia, pleuritis, pneumothorax, - msk - arthritis, spasm, bone tumor - neural - herpes zoster - GI - ulcer, bowel disease, pancreatitis - anxiety/depression mechanism: - supply-demand mismatch in coronary arteries --> hypoxia in myocardium --> presentation: - diffuse retrosternally - left arm, jaw, back - aching, dull, pressing, squeezing - mild to severe - lasts for minutes - worse with effort (not better with posture) - better with rest

Question 223

Describe the causes and presentation of dyspnea

Answer 223

Causes: - cardiac - LVHF, mitral stenosis - pulm - pulm embolism, pulm hypertension, asthma Presentation: - orthopnea - SOB when flat - PND - SOB that wakes when sleeping - dyspnea on exertion - SOB while walking

Question 224

Describe friction rub due to pericardial disease and the heart sounds heard

Answer 224

- pericarditis --> ventricles rub against pericardium | - rough raspy sound

Question 225

Describe the heart sounds heard during aortic regurgitation

Answer 225

- diastolic murmur heard along left sternal border - systolic murmur heard in aortic area - diastolic pressure falls due to lowered resistance and inc dilation of arterioles - carotid pulsing is visible - quincke's pulse (blanching and pulse in fingernails) - does not vary with inspiration

Question 226

Describe the heart sounds heard during aortic stenosis

Answer 226

- aortic valve opening is smaller - inc in LV pressure - murmur occurs with pulse upstroke and is systolic - distinct sound in S2

Question 227

Describe the heart sounds heard during hypertrophic cardiomyopathy

Answer 227

- similar to stenosis --> hear a rough murmur followed by a distinct second heart sound - S1 and S2 merge into one plateaued sound

Question 228

Describe the heart sounds heard in mitral regurgitation

Answer 228

- plateau murmur (less harsh) at apex - see movement of stethoscope on systole - S3 - mid-diastolic murmur - in mitral valve prolapse --> left late systolic murmur and mitral click late in systole

Question 229

Describe the heart sounds heard in mitral stenosis

Answer 229

- rheumatic heart disease - poor filling of LV due to MV narrowing - opening snap that immediately follows S2

Question 230

Describe the heart sound S3

Answer 230

- occurs after S2 mid diastole (ken-tu-cky) - heard with bell in LLD - sign of LV volume overload

Question 231

Describe the heart sound S4

Answer 231

- occurse right before S1 at end of diastole - sign of a stiff LV - LV is stiff and aorta pushing against stiff LV makes that sound during atrial contraction

Question 232

What would a systolic ejection murmur indicate?

Answer 232

- aortic or pulmonic stenosis | - crescendo-decrescendo

Question 233

What would a pansystolic or holosystolic murmur indicate?

Answer 233

- mitral or tricuspid regurgitation | - uniform throughout S1 to S2

Question 234

What would a late systolic murmur indicate?

Answer 234

- mitral valve prolapse

Question 235

What would an early diastolic murmur indicate?

Answer 235

- aortic regurgitation - decrescendo - high pitched

Question 236

What would a mid to late diastolic murmur indicate?

Answer 236

- mitral stenosis | - opening snap followed by decrescendo murmur that intensifies at end of diastole with atrial kick

Question 237

Name the most common primary cardiac neoplasms in (a) infants/children and (b) adults

Answer 237

a) rhabdomyoma: benign skeletal muscle cell tumor | b) angiosarcoma: malignant tumor of blood vessels

Question 238

Name the most common location and possible complications of a cardiac myxoma

Answer 238

- usually in LA - mitral valve involvement - can embolize - can cause syncope of sudden death

Question 239

Identify the types of organisms that may infect the myocardium

Answer 239

- viral: coxsackie virus - bacterial: chlamydiae, rickettsiae - fungal: candida - parasitic: protozoa, helminths

Question 240

Identify at least one autoimmune disease that can affect the heart and the areas of the heart that may be affected

Answer 240

- collagen vascular disease/connective tissue disease - heart involved as pat of systemic disease - can involve pericardium, myocardium, endocardium - can have vessel inflammation --> vasculitis --> infarcts

Question 241

Give examples of substances that may be responsible for toxic cardiomyopathy

Answer 241

- meds: adriamycin (used for chemo) | - exogenous substances: - ethanol, cobalt

Question 242

Identify the disease where proteins deposit around blood vessels and in organ parenchyma. Name a malignancy commonly associated with this disease process

Answer 242

- amyloidosis: protei deposition in blood vessels and organ parenchyma - usually with plasma cell neoplasm - wax like consistency of organs

Question 243

Define the following terms: myocarditis, primary cardiomyopathy and secondary cardiomyopathy

Answer 243

primary cardiomyopathy: - anatomic or metabolic myofiber abnormality - dilated, hypertrophic, or restrictive CM secondary cardiomyopathy: - ischemia - hypertension - valve disease - pericardial constriction

Question 244

Give examples of causes of restrictive cardiomyopathy

Answer 244

- impairment of compliance --> diastolic dysfunction - idiopathic, amyloidosis, radiation induced fibrosis - pericardial constriction - problem with heart relaxing, but not necessarily due to hypertrophy

Question 245

For hypertrophic cardiomyopathy, dilated cardiomyopathy, and restrictive cardiomyopathy, describe the macroscopic appearance of the heart, the functional problem and the prevalence of genetic mutations associated with that condition

Answer 245

HCM: - macroscopic: thick heart and cannot relax well; hypertrophic disarray - functional problem: thickened LV wall; septum can be more thicker and obstruct outflow - genetic mutations: 50-100% due to genetic mutations (myosin binding protein C, beta myosin heavy chain, cardiac troponin T) DCM: - macroscopic: LV gets really dilated --> inc wall stress so cannot pump as well - functional problem: impaired contractility - genetic mutations: 30-40% have associated mutations (desmin, dystrophin, sarcoglycans, lamin A/C) RCM: - macroscopic: amyloid deposition, radiation induced fibrosis - functional problem: cannot relax during diastole - genetic mutations: acquired, not usually genetically linked

Question 246

What is cardiac myxoma?

Answer 246

- benign neoplasm - common in teens and adults - LA more often than RA - mitral valve involvement - can embolize

Question 247

Discuss the effects of systemic hypertension

Answer 247

- affects left heart - sustained afterload --> concentric hypertrophy of LV - atherosclerosis - aneurysm - renal disease

Question 248

Discuss the effects of pulmonary hypertension.

Answer 248

- affects right heart - usually caused by LHF - see concentric hypertrophy if afterload increased in pulmonary circuit - see congestion of liver and peripheral edema

Question 249

Define cor pulmonale and be able to give examples of underlying causes

Answer 249

- when pulmonary dysfunction/fluid build up leads to right sided heart failure

Question 250

Discuss the incidence and complications of a bicuspid aortic valve.

Answer 250

- fusion of 2/3 leaflets in aortic valve - happens in .5-2% of pop with M>F - can cause reduced outflow --> LVH - increased turbulence --> valve thickening and stenosis

Question 251

Identify the most common causes of aortic stenosis in patients 70 years of age

Answer 251

- bicuspid 70

Question 252

Describe the key features of rheumatic heart disease, including: changes to valve leaflets and chordae tendinea, and effects on valve function

Answer 252

- post-infection AI response - pancarditis - endocarditis: valve damage --> fibrosis --> vegetation formation on valves - myocardium: myocarditis - pericardium: fibrinous pericarditis

Question 253

Identify the most commonly affected valves in rheumatic heart disease

Answer 253

- mitral and aortic valve disease

Question 254

Distinguish the two major classes of cardiac valve vegetations.

Answer 254

1) sterile/non-bacterial: - thrombus formation on valve - damaged valve - may lead to embolism, valve function deficits, potential for infection

Question 255

Describe the possible complications of endocarditis.

Answer 255

- inflammation of endocardium (valves) --> fibrosis - MV > AV - fibrosis, fusion, calcification of leaflets and cusps - fibrosis, fusion, shortening of chordae tendinae - valves can't open (stenosis) or close (regurg) -->HF - susceptible to infective endocarditis

Question 256

Describe the clinical presentation and possible outcomes of acute myocarditis

Answer 256

Presentation: - viral cause usually - young age - resp or GI problems - fever, angina, arrhythmia, HF - lymph infiltrations of myocytes --> damage to myocytes

Question 257

List the anatomic classes and features of cardiomyopathies

Answer 257

HCM: DCM: - myocardial dilation with compensatory hypertrophy - low systolic function - usually idiopathic - RAAS act leads to remodeling - volume overload - dyspnea, orthopnea, PND - S3 gallop due to very compliant LV - treat with beta blockers, ACEis, and ARBs, and AAs RCM:

Question 258

Describe the causes, pathophysiology and management of hypertrophic cardiomyopathy

Answer 258

Causes: - 50-100% genetic - Pathophys: - hypertrophy - myocyte disarray - sarcomeres added in parallel --> concentric hypertrophy- septum more enlarged - high EF - outlflow obstruction - DOE, angina, - systolic murmur that gets louder with standing/valsalva Management: - avoid overexertion - beta blockers, verapamil - surgical myomectomy of septum - alcohol ablation of hypertrophic cells - ICD - transplant

Question 259

Describe the etiologies and clinical presentation of restrictive cardiomyopathy

Answer 259

- normal to reduced ventricular volume - normal ventricular wall thickness - amyloidosis and sarcoidosis