Chapter 13: Drugs Used in Heart Failure

Question 1

What is the fundamental physiologic defect in heart failure?

Answer 1

Decrease in cardiac output

Question 2

The graph that relates cardiac output, stroke volume, etc, to filling pressure or end-diastolic fiber length; also known as the Frank-Starling curve

Answer 2

Ventricular function curve

Question 3

A drug that inhibits one or more enzymes that degrade cAMP (and other cyclic nucleotides)

Answer 3

PDE inhibitor

Question 4

An arrhythmia consisting entirely or largely of beats originating below the AV node

Answer 4

Ventricular tachycardia

Question 5

Electrical effects (early responses) of cardiac glycosides:

Answer 5

1. Increased PR interval, caused by the decrease in atrioventricular (AV) conduction velocity
2. Flattening of the T wave

Question 6

What is the most important manifestation of digitalis toxicity?

Answer 6

Increased automaticity, caused by intracellular calcium overload

Question 7

Effects of digitalis

Answer 7

1. Slow ventricular rate.
2. Shortened QT interval
3. Inversion of the T wave
4. ST segment depression

Question 8

Digitalis toxicity, especially arrhythmogenesis, is increased by:

Answer 8

1. Hypokalemia
2. Hypomagnesemia
3. Hypercalcemia

Question 9

The major signs of digitalis toxicity

Answer 9

1. Arrhythmias
2. Nausea
3. Vomiting
4. Diarrhea.

Rarely, confusion or hallucinations and visual or endocrine aberrations may occur.

Question 10

Treatment of digitalis toxicity

Answer 10

1. Correction of potassium or magnesium deficiency
2. Antiarrhythmic drugs
3. Digoxin antibodies

Question 11

What is the first-line therapy for both systolic and diastolic failure and are used in heart failure?

Answer 11

Diuretics are used before digitalis and other drugs are considered.

Question 12

Often useful in acute failure in which systolic function is markedly depressed, but they are NOT appropriate for chronic failure because of tolerance, lack of oral efficacy, and significant arrhythmogenic effects.

Answer 12

Beta1- Adrenoceptor Agonists

- Dobutamine and dopamine

Question 13

The use of these drugs is based on the reduction in cardiac size and improved efficiency that can be achieved with proper adjustment of venous return (preload) and reduction of impedance to ventricular ejection (afterload)

Answer 13

Vasodilators

- nitroprusside or nitroglycerin

Question 14

Reduces preload, edema by powerful diuretic action on thick ascending limb in nephron, and vasodilating effect on pulmonary vessels

Answer 14

Loop diuretics (e.g. Furosemide)

Question 15

Antagonist of aldosterone in kidney plus poorly understood reduction in mortality.

Side effects include hyperkalemia and gynecomastia

Answer 15

Spironolactone

Eplerenone: similar to spironolactone but lacks gynecomastia effect

Question 16

Blocks angiotensin-converting enzyme, reduces Ang II levels, decreases vascular tone and aldosterone secretion, and shown to reduce mortality

Answer 16

Angiotensin-converting enzyme (ACE) inhibitors

- Captopril

Question 17

Positive inotropic drug inhibiting Na /K ATPase sodium pump and increases intracellular Na , decreasing Ca2+ expulsion and increasing cardiac contractility

Answer 17

Cardiac glycosides: digoxin

Question 18

Beta1-selective sympathomimetic, increases cAMP and force of contraction

Answer 18

Sympathomimetics: dobutamine

Question 19

Poorly understood reduction of mortality, possibly by decreasing remodeling

Answer 19

Beta blockers

Question 20

Atrial peptide vasodilator, diuretic used in acute severe decompensated failure

Toxicity:
Renal damage, hypotension

Answer 20

Nesiritide