Cardiovascular anatomy

Question 1

What is the blood supply of the SA Node?

Answer 1

Commonly supplied by RCA (blood supply independent of dominance)

Question 2

What is the blood supply of the AV Node?

Answer 2

Supplied by the PDA

Question 3

Describe effects of PDA infarct

Answer 3

Infarct may cause AV nodal dysfunction (bradycardia or heart block)

Question 4

Describe the prevalence and features of a right-dominant circulation

Answer 4

85% of people PDA arises from RCA

Question 5

Describe the prevalence and features of a left-dominant circulation

Answer 5

8% of people, PDA arises from LCX

Question 6

Describe the prevalence and features of a Codominant circulation

Answer 6

7% of people, PDA arises from both LCX and RCA

Question 7

What is the most common site of coronary artery occlusion?

Answer 7

Coronary artery occlusion most commonly occurs in the LAD

Question 8

When does coronary blood flow peak?

Answer 8

Coronary blood flow peaks in early diastole

Question 9

The left circumflex coronary artery supplies?

Answer 9

Supplies lateral and posterior walls of left ventricle, anterolateral papillary muscle

Question 10

LCX AKA

Answer 10

Left circumflex coronary artery

Question 11

LAD AKA

Answer 11

Left anterior descending coronary artery

Question 12

LAD supplies

Answer 12

Anterior 2/3 of interventricular septum, anterolateral papillary muscle, anterior surface of the left ventricle

Question 13

PDA AKA

Answer 13

Posterior descending/interventricular artery

Question 14

PDA supplies

Answer 14

AV node, posterior 1/3 of interventricular septum, posterior 2/3 walls of ventricles and posteromedial papillary muscle

Question 15

Right acute marginal artery supplies

Answer 15

Right ventricle

Question 16

What is the most posterior part of the heart?

Answer 16

Left atrium

Question 17

Left atrial enlargement can cause?

Answer 17

Dysphagia, (due to compression of the esophagus), or hoarseness (due to compression of the left recurrent laryngeal nerve, a branch of the vagus nerve)

Question 18

What are the layers of the pericardium?

Answer 18

From outer to inner Fibrous pericardium Parietal layer of serous pericardium Visceral layer of serous pericardium

Question 19

Where is the pericardial cavity?

Answer 19

Lies between parietal and visceral layers of the pericardium

Question 20

Innervation of the pericardium

Answer 20

Phrenic nerve

Question 21

Pericarditis pain location

Answer 21

Can cause referred pain to the shoulder

Question 22

CO equation

Answer 22

SV x HR = CO

Question 23

Fick Principle

Answer 23

Rate of O2 consumption / (arterial O2 content - venous O2 content)

Question 24

MAP equation

Answer 24

MAP = CO x TPR

Question 25

MAP at resting HR

Answer 25

(2/3 diastolic + 1/3 systolic)

Question 26

Pulse pressure equation

Answer 26

Systolic pressure - diastolic pressure

Question 27

Pulse pressure is proportional to?

Answer 27

SV

Question 28

Pulse pressure is inversely proportional to?

Answer 28

Arterial compliance

Question 29

SV equation

Answer 29

EDV - ESV

Question 30

Describe CO control in exercise

Answer 30

During the early stages of exercise CO is maintained by Increased HR and increased SV During the late stages of exercise CO is maintained only by increased HR as SV plateaus

Question 31

Increased HR effect on SV

Answer 31

Diastole is shortened with increased HR because there is less filling time so CO is decreased such as in ventricular tachycardia)

Question 32

Causes of increased pulse pressure

Answer 32

* Hyperthyroidism * Aortic regurgitation * Aortic stiffening (isolated systolic hypertension in the elderly) * Obstructive sleep apnea (increased sympathetic tone) * Anemia * Exercise (transient)

Question 33

Causes of decreased pulse pressure

Answer 33

* Aortic stenosis * Cardiogenic shock * Cardiac tamponade * Advanced heart failure

Question 34

SV is increased by

Answer 34

* Increased contractility * Increased preload * Decreased afterload

Question 35

SVCAP

Answer 35

Stroke volume is affected by contractility, afterload and preload

Question 36

Contractility (and SV) are increased with

Answer 36

* Catecholamine stimulation via B1 receptor * Increased intracellular Ca2+ * Decreased extracellular Na+ (reduced activity of Na/Ca exchanger) * Digitalis (bocks Na/K pump -\> increased intracellular Na -\> decreased Na/Ca exchanger activity -\> increased intracellular Ca

Question 37

Describe the pathway of B1 stimulation

Answer 37

* Ca channels phosphorylated -\> increased Ca entry -\> increased Ca-induced Ca-release and increased Ca storage in the sarcoplasmic reticulum * Phospholamban phosphorylation results in active CaATPase -\> increased Ca storage in the sarcoplasmic reticulum

Question 38

Describe Phospholamban phosphorylation

Answer 38

results in active CaATPase -\> increased Ca storage in the sarcoplasmic reticulum

Question 39

Describe the function of digitalis

Answer 39

Digitalis blocks the Na/K pump -\> increased intracellular Na -\> decreased Na/Ca exchanger activity -\> increased intracellular Ca and thereby increasing contractility

Question 40

Contractility is decreased by

Answer 40

* B1 blockade (decreased cAMP) * HF with systolic dysfunction * Acidosis Hypoxia/hypercapnia (decreased PO2/ increased PCO2) * Non-dihydropyridine Ca2 channel blockers

Question 41

How is preload determined?

Answer 41

It is approximated by ventricular EDV and depends on venous tone and circulating blood volume

Question 42

Venous vasodilators effect on preload

Answer 42

Decrease preload

Question 43

Nitroglycerin effect on venous circulation

Answer 43

Venous vasodilation and decreased preload through reduced venous return

Question 44

How is afterload determined?

Answer 44

Afterload is approximated by MAP Increased afterload -\> increased pressure -\> increased wall tension per Laplace's Law

Question 45

What is the adaptive response to increased afterload?

Answer 45

The left ventricle compensates for increased afterload by thickening (hypertrophy) in order to reduce wall tension

Question 46

Arterial vasodilators affect on afterload

Answer 46

Decrease afterload

Question 47

ACE inhibitors affect on afterload and preload

Answer 47

Decrease afterload and preload

Question 48

Chronic hypertension (MAP) leads to what heart changes?

Answer 48

LV hypertrophy

Question 49

Myocardial O2 demand is increased by?

Answer 49

* Increased contractility * Increased afterload * Increased heart rate * Increased diameter of the ventricle (increased wall tension)

Question 50

Wall tension principle

Answer 50

LaPlace's Law