Heart Failure - Auchampach

Question 1

What is heart failure?

Answer 1

Inability of the heart to pump blood equal to the metabolic rate of the body

Question 2

What is the formula for cardiac output?

Answer 2

CO=heart rate*stroke volume

Question 3

What factors influence stroke volume? Do they increase or decrease stroke volume?

Answer 3

Contractility- Increase
Preload-Increase
Afterload-Decrease

Question 4

How is ‘preload’ measured?

Answer 4

Left Ventricle End Diastolic Volume (or pressure?)

IE: how much blood can be loaded into the left ventricle

Question 5

What is afterload?

Answer 5

Resistance the ventricle overcomes to empty it’s contents

IE: the pressure in the aorta

Question 6

What can change contractility?

Answer 6

Availability of intracellular calcium

Question 7

What is compliance?

Answer 7

The change in pressure caused by an increase in volume

Question 8

When does isovolumic contraction occur?

answer for the left side of the heart

Answer 8

After the closure of the mitral valve

Question 9

When does isovolumic relaxation occur?

answer for the left side of the heart

Answer 9

After the closure of the aortic valve

Question 10

What are three general causes of heart disease?

Answer 10

Impaired Ventricular Contractility
Increased Afterload
Impaired Relaxation/Filling

Question 11

What are two ways to classify heart failure? Which typically combine?

Answer 11

Diastolic dysfunction vs Systolic dysfunction
Reduced Ejection Fraction vs Preserved Ejection Fraction

Diastolic dysfunction usually pairs with preserved EF
Systolic dysfunction usually pairs with reduced EF

Question 12

What are some causes of increased afterload?

Answer 12

Hypertension

Aortic Stenosis

Question 13

What are some causes of impaired contractility?

Answer 13

Coronary Ischemias (transient or infarction)
Overload caused by regurgitations
Cardiomyopathy

Question 14

What are some causes of impaired relaxation/filling?

Answer 14

Left ventricle hypertrophy
Myocardial fibrosis
Pericardial constriction/tamponade

Question 15

What is unique about the right side of the heart? What does this mean in terms of heart failure?

Answer 15

RV has high compliance

Right-sided heart failure typically due to an increase in afterload and is SECONDARY TO LUNG DYSFUNCTION

Question 16

What are some examples of neurohormonal activation in response to decrease cardiac output?

Answer 16

Sympathetic activation
Renin-Angiotensin-Aldosterone activation
Anti-diuretic hormone

Question 17

Why is neurohormonal control not a viable long-term solution to heart failure?

Answer 17

CV system is a closed loop! You can not increase preload without eventually increasing afterload, leading to decrease cardiac output.

Question 18

What are some (very general) causes of heart failure?

Answer 18

Increased metabolic demand
Increased circulating volume
Increased afterload
Decreased contractility
Bradycardia

Question 19

What would increase metabolic demand?

Answer 19

Fever
Infection
Anemia
Hyperthyroidism 
Pregnancy

Question 20

How does the heart association classify heart failure?

Answer 20

Class I- no limitation in physical activity
Class II- dyspnea, fatigue with moderate exertion
Class III- dyspnea with minimal exertion
Class IV- dyspnea at rest

Question 21

What is the prognosis of heart disease?

Answer 21

5 year mortality rate is 45-60%

Class II or high is 60% mortality rate

Question 22

What are the 4 goals of treating systolic heart failure?

Answer 22

Fix underlying causes
Manage symptoms
Modulate neurohormonal response
prolong survival

Question 23

What are 5 classes of drugs used to treat heart failure with preserved ejection fraction? Why are these used?

Answer 23

Diuretics 
Renin-Angiotensin-Aldosterone Inhibitors
Beta-blockers
Vasodilators
Positive Inotropic agents

Decrease afterload

Question 24

What is an example of a positive inotrope?

Answer 24

Digoxin

Question 25

What are Digoxin's primary effects? Secondary effects?

Answer 25

Primary - Increases contractility - Increases Stroke Volume - Slows Heart Rate Secondary - Arterial and Venous Dilation - Normalized Arterial Baroreceptors

Question 26

What is the mechanism of action for digoxin?

Answer 26

Inhibits the Na/K ATPase The decreased Na gradient decreases the power for the Ca/Na exchanger, meaning that Ca stays in the cell longer

Question 27

How does digoxin affect heart rate?

Answer 27

Increased activity of the vagal nerve leading to reduced firing at the SA node and decreased conduction at the AV node.

Question 28

What is seen on an ECG of a patient taking Digoxin?

Answer 28

Increased PR interval

Question 29

What are some negative effects of Digoxin?

Answer 29

- Affects all electrical systems (GI, visual, neuro, muscular) - Increased toxicity with hypokalemia - Multiple drug interactions

Question 30

When is Digoxin used?

Answer 30

- Heart failure patients with LV systolic dysfunction AND atrial fibrillation - Heart failure patients who have sinus rhythm despite maximal doses of other therapies

Question 31

How does Milrinone work?

Answer 31

Phosphodiesterase Inhibitor Positive inotrope that also produces vasodilation

Question 32

How do dobutamine and dopamine work?

Answer 32

Dobutamine -Beta1 receptor agonist, positive inotrope Dopamine -Simpathomimetic, positive inotrope

Question 33

Why are diuretics used to treat heart failure?

Answer 33

- reduced preload - reduced heart size - reduced edema

Question 34

What are three classes of diuretics? What is the main drug associated with each class?

Answer 34

- Loop diuretics (furosemide) - Thiazide diuretics (chlorothiazide) - K sparing diuretics (amiloride, triamterene)

Question 35

What is the main side effect of diuretic therapy? What can be done to prevent it?

Answer 35

hypokalemia prescribe K-sparing diuretics

Question 36

What does angiotensin do? What does aldosterone do?

Answer 36

Angiotensin causes aldosterone secretion; aldosterone causes water and sodium retention

Question 37

What are common ace inhibitors? Why are they prescribed for heart failure?

Answer 37

captopril, lisinopril, enalapril Decrease afterload and preload Increase survival rate

Question 38

What are some potential side effects of ACE inhibitors?

Answer 38

Dry cough Decreased renal function hyperkalemia when used with aldosterone antagonists

Question 39

What is an alternative for patients who can not tolerate ACE inhibitors?

Answer 39

Angiotensin Receptor blockers

Question 40

What do aldosterone antagonists do? What are some examples?

Answer 40

Block aldosterone to reduce edema, decrease fibrosis Spironolactone, eplerenone

Question 41

What do beta-adrenergic receptors antagonists do?

Answer 41

Decrease BP, arrythmias Increase ventricular function Decrease mortality rate

Question 42

What is important about dosing for beta-adrenergic receptor antagonists?

Answer 42

They can initially worsen cardiac function, so dose must start low and then increase.

Question 43

What is Neprolysin?

Answer 43

peptidase that degrades vasoactive peptides