Cardio Formulas and Cardiology Flashcards

1
Q

Velocity of blood flow

A

v = volume of blood flow/cross sectional area

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2
Q

Blood flow is also the

A

Ohm’s law

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3
Q

Blood flow formula

A

Flow rate = P1 - P2/Resistance

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4
Q

Tendnecy for turbulent flow =

A

Reynolds number = (velocity of blood flow x diameter x density) / viscosity

Re = vdp/n

cm/sec, cm

Greatest in proximal aorta and pulmonary artery

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5
Q

Resistance of the entire peripheral circulation =

A

TPR = 100mmHg (Pa - Pv)/ 100ml/sec (CO or blood flow)

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6
Q

Total pulmonary vascular resistance =

A

TPVR = (16 - 2)/100
(Pulmo artery pressure - left atrial pressure)/ 100 (CO, blood flow)

Total pulmo vascular resistance = 0.14 PRU

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7
Q

Conductace =

A

Conductance = 1/ resistance

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8
Q

Conduntance of vessel

A

inc in proportion to fourth power of diameter

C inc in proportion to fourth power of diameter

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9
Q

The great inc in conductance when diameter inc is exemplified by

A

Poiseuille’s law

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10
Q

Velocities of all concentric rings of flowing blood x areas of the ring

A

Poiseuille’s law

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11
Q

Poiseuille’s law =

A

Rate of Flow = pie(pressure difference between ends of vessels)radius raised to the 4th power / 8(viscosity)(length=1)

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12
Q

The greatest role of all factors in determining rate of blood flow

A

Diameter

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13
Q

2/3 of total systemic resistance to blood flow comes fr

A

arterioles

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14
Q

Arterioles regulate blood flow by

A

Turning off blood flow (arterioloconstriction) and inc flow by 256fold by arteriolodilation

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15
Q

The flow through artery, arteriole, cap, venule and vein are arranged in

A

Series

Rtotal = R1 + R2 + R3

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16
Q

Blood flow to organs are arranged in

A

Parallel

1/Rtotal = 1/R1 + 1/R2

Total conductance = C1 + C2

Amputation of limb or removal of kidney reduces total vascular conductance and total blood flow (CO) inc total peripheral vasc resistance

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17
Q

Viscosity of blood is

A

3x as great as water

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18
Q

Vascular distensibility =

A

Vascular distensibility = inc in volume / inc in pressure x original volume

fractional inc in volume for each millimeter of mercury rise in pressure

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19
Q

Vascular compliance =

A

VC = inc in volume/inc in pressure

Compliance = distensibility x volume

So a highly distensible vessel may have far less complaince than a vessel with large volume

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20
Q

Pulse pressure =

A

pulse pressure = stroke volume/arterial compliance

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21
Q

Damping =

A

Damping = resistance x compliance

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22
Q

MAP is not just average of systolic and diastolic pressure bec

A

Bec greater fraction of cardiac cycle is spent in diastole

60 Diastolic
40 Systolic

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23
Q

MAP =

Averahe arterial pressure with respect to time

A

MAP = (SBP + 2DBP)/3

Diastolic pressure + 1/3 of pulse pressure

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24
Q

Four primary forces determining fluid movement in capillary membrane:

A

Starling forces
1 Capillary pressure
2 Interstitial fluid pressure
3 Capillary plasma colloid osmotic pressure
4 Interstitial fluid colloid osmotic pressure

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25
Q

Net Filtration Pressure =

A

NFP = (Pc-Pif)-(Plasmacoll+Ifcolloid)

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26
Q

Filtration=

A

Filtration= capillary filtration coeff x NFP

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27
Q

Plasma colloid osmotic pressure is 28 mmHg; 19 by proteins and 9 by Na, potassium and cations. Extra osmotic pressure is called

A

Donnan effect

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28
Q

Physiologic properties of the heart:

A

All or none principle
No fatigue, no tetany
Duration of cardiac muscle contraction is a function of the duration of the action potential

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29
Q

Is the principle that the strength by which a nerve or muscle fiber responds to a stimulus is not dependent on the strength of the stimulus

A

All-or-none Law

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30
Q

If the stimulus is any strength above threshold, the nerve or muscle fiber will give a complete response or otherwise no response at all

A

All-or-none law

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31
Q

Increase in contractility

A

Positive inotropic effect

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32
Q

Decrease in contractility

A

Negative inotropic effect

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33
Q

Ability to initiate its own beat

Ability to generate spontaneous action potential

A

Automaticity

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34
Q

Regularity of such pacemaking activity

A

Rhythmicity

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35
Q

Fibers of SA node connect with surrounding atrial muscles

A

Conductivity

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36
Q

Conduction velocity in atrial muscle

A

0.3-0.5 m/sec

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37
Q

Ability of the heart to initiate an action potential in response to an inward depolarizing current

A

Excitability

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38
Q

Smallest branches of the arteries

A

Arterioles

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39
Q

The site of highest resistance in the cardiovascular system

Alpha 1 and beta 2 adrenergic

A

Arterioles

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40
Q

Arteriole SNS receptors

A

Alpha 1 and beta 2 adrenergic

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41
Q

Contains the highest proportion of blood in the cardiovascular system

Largest total unstressed blood volume

Thin walled

Low pressure

Alpha 1 adrenergic

A

Veins

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42
Q

Gas and nutrients exchange in the cardiovascular system

Largest total cross sectional and surface area

A

Capillaries

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43
Q

A collapsed larger lumen
Thin wall

No Internal elastic lamina
Tunica media has large quantity of collagen (few smooth muscles and less elastic fibers) that is the reason they are easily compressed

Tunica adventitia is thicker than tunica media in large veins

Presence of valves to prevent back flow

A

Medium sized vein

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44
Q

Thick wall
Arteries retain their patency
Internal elastic lamina is present only in arteries
Tunica media is thicker than adventitia

A

Medium sized artery

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45
Q

Inotropic drugs

A

Dopamine

Dobutamine

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46
Q

Pacemaker of heart

Located near:

A

SA Node

Sulcus terminalis and SVC as it enters the right atrium

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47
Q

Formed bt the left and right brachiocephalic/innominate vein

A

SVC

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48
Q

Level at which the SVC is formed

A

1st right costal cartilage

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49
Q

Send blood from the heart
High pressure
Narrow lumen diameter
Thick walled

Wall layers:
T. Adventiria
T. Media
T. Intima

Large amounts of muscle and elastic fibers

No valves

A

Arteries

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50
Q

Change in HR

A

Chronotropic

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51
Q

Change in conduction velocity

A

Dromotropic

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52
Q

Send blood to the heart
Low pressure
Wide lumen diameter
Thin walled

Wall layers:
T. Adventitia
T. Media
T. Intima

Small amounts of muscle and elastic fibers

With valves

A

Veins

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53
Q

Thick walled

Extensive elastic tissue and muscles

A

Artery

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54
Q

Material exchange with tissues
Low pressure
Extremely narrow lumen diameter
Extremely thin walled

Wall layers:
T. Intima

No muscle and elastic fibers

No valves

A

Capillaries

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55
Q

Receives blood from left ventricle

A

Aorta

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56
Q

Transport under high pressure, strong vascular walls

A

Arteries

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57
Q

Control conduits, last branch of arterial system, strong muscular walls that can strongly constrict or dilate

A

Arteriole

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58
Q

Exchange substances through pores

A

Capillaries

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59
Q

Collect blood from capillaries

A

Venules

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60
Q

Low pressure, transport blood back to the heart, controllable reservoir of extra blood

A

Veins

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61
Q

Means blood flows crosswise in the vessel and along the vessel

Forms whorls in the blood called

A

Turbulence

Eddy currents

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62
Q

Normal blood flow is

A

Laminar

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63
Q

Turbulence occurs when

A
Radius is large (aorta)
Velocity is large (cardiac output)
Vessel diameter (arterial stenosis)
Low viscosity (anemia) 
Density of blood
64
Q

Reynolds number of 2000 or less is

A

Laminar

65
Q

Reynolds number is inversely proportional to the

A

viscosity

66
Q

Pressure gradient and blood flow

A

directly proportional

67
Q

Pressure gradient and viscosity

A

Directly proportional

68
Q

A high Reynolds number meant

A

A high possibility of turbulence

69
Q

Pressure gradient and length

A

Directly proportional

70
Q

Pressure gradient and fourth power of radius

A

Inversely proportional

71
Q

Pressure gradient and flow rate

A

Directly proportional

72
Q

Flow rate and vascular resistance

A

Inversely proportional

73
Q

Volume of blood passing through per unit of time

A

Flow rate

74
Q

Difference between the systolic and diastolic pressures

SBP-DBP

A

Pulse pressure

75
Q

Most inportant determinant of pulse pressure

A

Stroke volume

76
Q

Pulse pressure is increased in aging population because of

A

Decreased capacitance

77
Q

MAP is maintained at

A

110-130

78
Q

MAP also =

A

CO x SVR + CVP

79
Q

The highest arterjal pressure during a cardiac cycle

Occurs when the heart contracts and blood is ejected into the arterial system

A

Systolic pressure

80
Q

Lowest arterial pressure in the cardiac cycle

Occurs when the heart is relaxed and blood is being returned to the heart via the veins

A

Diastole

81
Q

Fall in the pressure by 20mmHg and or >10 mmHg diastolic in resposne to moving from supine to standing

A

Orthostatic hypotension

82
Q

At least 2 separate clinic-based measurements

> 140/90 mmHg
and at least 2 non clinic measurements <140/90 mmHg in the absence of end organ damage

A

White coat hypertension

83
Q

PD
Rigidity, tremors
Dysautonomia
Hypotension

A

Shy-Drager syndrome

Multiple Systems Atrophy

84
Q

Cardiac Output =

A

CO = HR x SV

85
Q

Cardiac reserve

If resting, CO is

After exercise,

A

6L/min

Inc to 21 L/min

Cardiac reserve?

CR = 21-6 L/Min

86
Q

Atrial contraction forces blood into ventricles

P wave
Atrial depolarization

A

Atrial systole

87
Q

Ventricular contraction pushes AV valves closed

AV Closure

QRS Complex
Ventricle depolarization

A
Ventricular systole (first phase)
Atrial Diastole
88
Q

Semilunar valves open and blood is ejected

T wave ventricular repolarization

A

Ventricular systole second phase

Atrial diastole

89
Q

Absence of p wave is seen in

A

atrial fibrillation

90
Q
Preceded by the p wave
Activation of stria
Contributes to ventricular filling
Increase in atrial pressure (A wave)
Ventricular hypertrophy
Fourth heart sound
A

Atrial systole

91
Q

Begins at QRS complex
Activation of ventricles
AV valves close when V pressure is greater than A pressure
Closure of AV valves -> S1, ventricular pressure increases, no blood leaves yet because aortic valve is CLOSED
constant ventricular volume

A

Isovolumetric ventricular contraction

92
Q

Max V pressure
C wave on venous pulse curve due to bulging of tricuspid valve intro right atrium, aortic valve opens
Ventricular volume decreases dramatically
Atrial filling begins
Onset of T wave (repolarization)

A

Rapid ventricular ejection

93
Q

Slower ejection of blood
Ventricular pressure decrease
Aortic pressure decreases
Runoff of blood from large arteries to smaller arteries
Atrial filling
V wave (blood flow into right atrium, rising phase)
Flow to right atrium into right ventricle (falling phase)

A

Reduced ventricular ejection

94
Q

Chambers relax and blood fills ventricles passively

A
Ventricular diastole (late) 
Atrial diastole
95
Q

SV =

A
SV = EDV - ESV
Normal = 120-50 = 70ml
96
Q

Ejection fraction =

A

EF = SV/EDV

Normal is 70/120 = 58%

97
Q

Extrinsic control of Stroke Volume: SNS

A
Arterial muscle (increases contractility)
Ventricular muscle (increases contractility)
Adrenal medulla (increase epinephrine augments the sympathetic actions on the heart)
Veins (increase venous return)
98
Q

Contraction of atria

Absent in atrial fibrillation

A

A wave

99
Q
Ventricular contraction (tricuspid bulges) 
Won’t see
A

C wave

100
Q

There are two positive waves

One occuring just before the first heart sound or the carotid impulse

One just after

When HR is 80 or less, they are fairly easy to time. But if the heart rate is fast, you may need to asucultate while you observe.

A

A (atrial contraction, absent in atrial fibrillation)

V waves

101
Q

Descent

Atrial relaxation

A

X wave

102
Q

Atrial venous filling

Occurs at the same time of ventricular contraction

A

V wave

103
Q

Descent
Ventricular filling
Tricuspid opens

A

Y descent

104
Q

Intrinsic control of SV

A

Inc strength of cardiac contraction
Inc EDV
Inc venous return

105
Q

Conditions with elevated a wave

Resistance to atrial emptying may occur at or beyond the tricuspid valve

A

Pulmonary hypertension
Rheumatic tricuspid stenosis
Right atrial mass or thrombus

106
Q

Large positive venous pulse during a wave

It occurs when an atrium contracts against a closed tricuspid valve during AV dissociation

A

Premature atrial/junctional/ventricular beats
Complete atrio-ventricular (AV) block
Ventricular tachycardia

107
Q

Most common cause of elevated v wave

A

Tricuspid regurgitation

Lancisi sign

108
Q

The ventricle contracts and if the tricuspid valve does not close well, a jet of blood shoots into the right atrium

Tricuspid regurgitation if significant will be accompanied by a pulsatile liver (feel over the lower costal margin)

You will also hear the murmur of tricuspid regurgitation - a pansystolic murmur that increases on inspiration

A

Elevated v wave

109
Q

Neck veins rise in inspiration rather than fall

Seen in pericardial tamponade
Right heart failure
Acute right ventricular MI

A

Kussmaul’s sign

110
Q

Exaggerated x wave or diastolic collapse of the neck veins

From constrictive pericarditis

A

Friedrich’s sign

111
Q

Initial depolarization of ventricle

Conduction velocity through AV node

A

PR interval

112
Q

Ventricular depolarization

A

QRS Complex

113
Q

Entire ventricular depolarization and repolarization

A

QT interval

114
Q

Muscle length prior to contractility

It is dependent of ventricular filling or EDV

A

Preload

115
Q

Period when ventricles are depolarized

A

ST segment

116
Q

Ventricular repolarization

A

T wave

117
Q

Preload =

A

EDV

118
Q

RMP of ventricle, atria and Purkine

A

-90mV

119
Q

Upstroke

Increase in Na conductance

A

Phase 0

120
Q

Initial repolarization
Brief
K ions move out
Na decrease conductance

A

Phase 1

121
Q

Plateau

Transient increase in calcium conductance, inward Ca

A

Phase 2

122
Q

Calcium conductance decrease
K increase
Membrane hyperpolarizes

A

Phase 3

123
Q

Resting membrane potential

A

Phase 4

124
Q

This value is related to right atrial pressure

A

Preload

125
Q

Most important determining factor for preload is

A

venous return

126
Q

Conduction system

A

SAN -> AVN -> AV bundle -> Bundle branches -> Purkinje fibers

127
Q

The tension or arterial pressure against which the ventricle must contract

If arterial pressure increases,
this also increases

A

Afterload

128
Q

Provides direct flow of current from the atrium to ventricle

A

Cardiac skeleton

129
Q

Slowest velocity of conduction is in the

A

AV Node

130
Q

Fastest conduction of velocity in the

A

Purkinje fiber

131
Q

Afterload =

A

End systolic wall stress

Resistance

132
Q

AV Node is in

A

Triangle of Koch

133
Q

Boundaries of Triangle of Koch

A

Septal leaflet of tricuspid valve
Opening of coronary sinus
Tendon of Todaro

134
Q

SA NODE aka

A

Node of Keith and Flack

135
Q

Lies in the sulcus between superior vena cava and right atrium

Exhibits self excitation

A

SA Node

136
Q

RMP of SA Node

A

-55 mv to -60 mv

137
Q

Volume of blood pumped per minute

CO = HR (75) x SV (70)

About 5.25 L/min

A

Cardiac output

138
Q

Difference between resting and maximal cardiac output

A

Cardiac reserve

139
Q

Volume of blood that filles the ventricle during diastole or relaxation

A

EDV

120 ml

140
Q

Anterior internodal pathway

A

Bachmann

141
Q

Middle internodal pathway

A

Wenkebach

142
Q

Posterior internodal tract

A

Thorel

143
Q

Volume of blood remaining in ventricle after systole

A

ESV

50 ml

144
Q

Difference between EDV and ESV

A

Stroke volume

145
Q

Found in the posterior wall of the right atrium
Behind the tricuspid valve near the opening of the coronary sinus

Delay of impulse transmission
Small bundle fibers
Less number of gap junctions

A

Atrio-Ventricular Node

146
Q

Divides into one single right bundle branch and 2 branches of left bundle (anterior and posterior fascicles)

A

His Bundle

147
Q

Merges with myocardial fibers
Conduction velocity is rapid
Higjly permeable gap junctions
Large fibers

A

Purkinje system

148
Q

CV Response to exercise

Central command

A

Inc Sympathetic outflow
Dec Parasympathetic outflow

Inc heart rate
Inc contractility
Inc cardiac output
Constriction of arterioles (splanchnic and renal)
Constriction of veins 
Inc venous return 

Inc blood flow to skeletal muscle

149
Q

Exercise

Local responses

A

Inc vasodilator metabolites
Dilation of skeletal muscle arterioles
Dec TPR

Inc blood flow to skeletal muscles

150
Q

Long QT syndrome pathogenecity genes

A

HERG gene (K channel gene chromosome 7)

SCN5A gene (Na gene chromosome 3) Brugada

syncope

151
Q

Polymorphic ventricular tachycardia
Hypokalemia
with long QT interval

A

Torsade de pointes

152
Q

Lead II, III, aVF

A

Inferior

153
Q

Lead I and aVL

V5, V6

A

Lateral

154
Q

Lead VI, V2

A

Septal

155
Q

V3, V4

A

Anterior