Cardiac Output

Question 1

MAP is proportional to?

Answer 1

HRSVSVR

Question 2

CO=

Answer 2

HR*SV

Question 3

Preload is defined as?

Answer 3

The amount of passive tension of the ventricular myocytes in the ventricles by the volume of blood just prior to contraction

Question 4

Preload is proportional to?

Answer 4

LVEDV/P

Question 5

Tension is proportional to?

Answer 5

Radius and pressure

Question 6

Preload is defined by the law of __

Answer 6

Laplace

Question 7

Stroke volume is dependent on which 3 factors?

Answer 7

Contractility, Preload, and (inversely proportional) to Afterload

Question 8

Increasing preload does what to stroke volume?

Answer 8

It increases stroke volume only up until a certain point of optimal sarcomere length

Question 9

Nitrates have what effects on HR, Preload, Afterload, contractility, Tone, and flow

Answer 9

Nitrates will do the following:
HR: Increase
Preload: DECREASE
Afterload: Decrease
CTY: No change
Tone: Decrease or no change
Flow: Increase or no change

Question 10

B-blockers have what effects on HR, Preload, Afterload, contractility, Tone, and flow

Answer 10

B-blockers will do the following:
HR: Decrease
Preload: No change
Afterload: No change
CTY: Decrease
Tone: Increase
Flow: No change

Question 11

Calcium channel-blockers have what effects on HR, Preload, Afterload, contractility, Tone, and flow

Answer 11

CCBs will do the following: 
HR: Decrease or no change
Preload: No change
Afterload: Decrease
CTY: Decrease
Tone: Decrease
Flow: Increase

Question 12

Increasing preload has what effect on oxygen demand?

Answer 12

Increasing preload will increase oxygen demand, thus myocardial oxygen demand is defined by preload

Question 13

How is preload regulated?

Answer 13

1. Venous tone (sympathetic activity increases tension in walls of veins and venules, thus increasing preload by forcing blood from veins into the heart)
2. Blood volume (increasing blood volume through fluid intake, neurohormonal mechanisms (RAAS, sympathetic nervous system, ADH)
3. Body position: Gravity affects venous return. Preload decreases when you stand up

Question 14

Myocardial demand is proportional to

Answer 14

preload, which is proportional to stroke volume. So in a way, myocardial demand is also proporitonal to stroke volume

Question 15

Afterload is determined by what 3 factors

Answer 15

1. Systemic vascular resistance (Systolic bp)
2. Aortic compliance
3. Aortic valve resistance

Question 16

Increasing afterload will do what to stroke volume?

Answer 16

Increasing afterload will decrease stroke volume

Question 17

Afterload is defined as

Answer 17

Ventricular the force against which the ventricle is working after initiation of contraction (i.e. the resistance against which the heart muscle works. Which is proportional to blood pressure and vascular stiffness/ SVR)

Question 18

Increasing afterload will have what effect on oxygen demand?

Answer 18

Increasing afterload will increase oxygen demand

Question 19

Acidosis will lead to vasoconstriction or vasodilation

Answer 19

vasodilation

Question 20

Hypoxia will lead to vasoconstriction or vasodilation

Answer 20

vasodilation

Question 21

Citrate/acetate will lead to vasoconstriciton or vasodilation

Answer 21

vasodilation

Question 22

Adenosine will lead to vasoconstriction or vasodilation

Answer 22

Vasodilation

Question 23

What are the 3 major determinants of oxygen demand?

Answer 23

Heart rate, wall tension, contractility. All are directly proportional to myocardial oxygen demand

Question 24

Chronic stable angina is mostly an issue with oxygen demand or oxygen supply?

Answer 24

Oxygen demand

Question 25

Acute coronary syndromes are treated by focusing on oxygen demand or oxygen supply?

Answer 25

Targeted at oxygen supply

Question 26

Catecholamines increased or decrease oxygen demand?

Answer 26

Increase

Question 27

Do B-blockers affect oxygen demand or oxygen supply? How do they affect either one?

Answer 27

- Decreased contractiliy and heart rate leads to decreased oxygen demand - Increased diastolic time increases myocardial oxygen supply

Question 28

What are the non selective B-blockers for B1 and B2? What do they treat?

Answer 28

Propranolol and nadolol; used for hyperthyroidism and portal hypertension

Question 29

What are the mixed B-blockers for B1, B2, and a1? What do they treat?

Answer 29

Carvedilol and labetalol; They treat heart failure (carvedilol) and hypertension (labetalol)

Question 30

What are the cardioselective B-blockers (B1>>B2)

Answer 30

Atenolol, metoprolol, and esmolol (antianginals)

Question 31

What are the contraindications for B-blockers?

Answer 31

Acute decompensated heart afilure, bradycardia/heart block (reflex tachycardia can be a problem in diabetics), bronchospasm, sexual dysnfunction, depression

Question 32

What are the AEs for non-dihydropyridines?

Answer 32

Worsening heart failure, bradycardia, AV nodal block, constipation (impairs smooth muscle function in gut)

Question 33

What are the AEs for dihydropyridines?

Answer 33

Hypotension, peripheral edema, headache, flushing ,dizziness

Question 34

What are the contraindications in general for calcium channel blockers?

Answer 34

Systolic heart failure, bradycardia, sinus node dysnfunction, AV nodal block

Question 35

Do Nitrates affect oxygen demand, oxygen supply, or both?

Answer 35

Both. DEMAND: NO from nitrates causes venodilation, decreased venous return/LVEDV, and decreased wall tension, thus decreasing oxygen demand. SUPPLY: Nitrates will causes arteriodilation, increased coronary blood flow, thus increasing oxygen supply

Question 36

What are the contraindications for nitrates?

Answer 36

Concomitant PDE5 inhibitor use (sildenafil, viagra)

Question 37

What are the side effects related to vasodilation and unrelated to vasodilation from nitrates?

Answer 37

Related to vasodilation: Hypotension, headaches (meningeal vessel dilatation), reflex tachycardia Unrelated to vasodilatation: Met-hemoglobinemia (oxidation of hemoglobin, rare)

Question 38

How long does it take for nitrate tolerance to occur?

Answer 38

Over the course of 1-3 weeks. Can be prevented by daily withdrawal of nitrates and may be due to depletion of reduced glutathione

Question 39

Indications for CABG over PCI?

Answer 39

- Left main stenosis>50% - 3-vessel CAD (LAD, LCx, RCA) - 2-vessel disease including LAD with low EF or Diabetes