Questions
DIRECTIONS: Each of the numbered items or incomplete statements in this section is followed by answers or by completions of the statement. Select the ONE lettered answer or completion that is BEST in each case.
1. Drugs that have been found to be useful in one or more types of heart failure include all of the following EXCEPT
(A) Na+/K+-ATPase inhibitors
(B) Alpha adrenoceptor agonists
(C) Beta adrenoceptor agonists
(D) Thiazide diuretics
(E) ACE inhibitors
2. The biochemical mechanism of action of digitalis is associated with
(A) A shortening of the action potential duration
(B) An increase in ATP synthesis
(C) A modification of the actin molecule
(D) An increase in systolic intracellular calcium levels
(E) A block of sodium-calcium exchange
3. A patient who has been taking digoxin for several years for chronic heart failure ii about to receive atropine for another condition. A common effect of digoxin (at therapeutic blood levels) that can be almost entirely blocked by atropine is'
(A) Tachycardia
(B) Decreased appetite
(C) Increased atrial contractility
(D) Increased PR interval on the ECG
(E) Headaches
Items 4-6: A 65-year-old woman has been admitted to the coronary care unit with a myocardial infarction.
4. If this patient develops acute severe congestive failure, all of the following might be useful EXCEPT
(A) Nitroprusside
(B) Digoxin
(C) Furosemide
(D) Propranolol
(E) Dobutamine
5. The patient might be given a cardiac glycoside. Important effects of digitalis on the heart include
(A) Increased force of contraction
(B) Decreased atrioventricular conduction velocity
(C) Increased ectopic automaticity
(D) Decreased ejection time
(E) All of the above
6. Which of the following situations constitutes an added risk of drug toxicity in this patient?
(A) Digoxin therapy in a patient with hypocalcemia
(B) Digoxin therapy in a patient with hyperkalemia
(C) Digoxin therapy in a patient with hypermagnesemia
(D) Digoxin therapy in a patient taking captopril
(E) Digoxin therapy in a patient taking quinidine
7. Which row in the following table correctly shows the major pharmacokinetic characteristics of the cardiac glycosides?
Row |
Variable |
Digoxin |
Digitoxin |
Ouabain |
(A) |
Oral bioavailability |
75% |
28% |
98% |
(B) |
Half-life |
168 hours |
36 hours |
20 hours |
(C) |
Volume of distribution |
6.3 L/kg |
0.6 L/kg |
18 L/kg |
(D) |
Percent protein bound in plasma |
50-60% |
> 90% |
40% |
(E) |
Organ of excretion |
Kidney |
Liver |
Liver |
8. Effects of digitalis on electrical functions of the heart include all of the following EXCEPT
(A) Prolonged atrioventricular refractory period
(B) Slowed sinoatrial nodal rate
(C) Increased atrial rate in atrial flutter
(D) Decreased ventricular rate in atrial fibrillation
(E) Decreased ectopic automaticity
9. Drugs associated with clinically useful or physiologically important positive inotropic effects include all of the following EXCEPT
(A) Amrinone
(B) Captopril
(C) Digoxin
(D) Dobutamine
(E) Norepinephrine
10. The effects of digoxin include all of the following EXCEPT
(A) Increased cardiac intracellular potassium
(B) Increased cardiac intracellular sodium
(C) Increased cardiac intracellular calcium
(D) Increased force of cardiac contraction
(E) Reduced sympathetic outflow to the heart
DIRECTIONS (Items 11-15): Each set of matching questions in this section consists of a list of four to twenty-six lettered options (some of which may be figures) followed by several numbered items. For each numbered item, select the ONE lettered option that is MOST closely associated with it. Each lettered option may be selected once, more than once, or not at all.
(A) Digibind antibodies
(B) Digitoxin
(C) Digoxin
(D) Dobutamine
(E) Enalapril
(F) Furosemide
(G) Lidocaine
(H) Magnesium
(I) Potassium
(J) Quinidine
11. Administration of this monovalent cation would tend to decrease or reverse a mild-to-moderate digitalis-induced arrhythmia
12. Shown to prolong life in patients with chronic congestive failure but has no direct positive inotropic action
13. A b1-selective agent sometimes used in acute congestive failure
14. Drug of choice in treating suicidal overdose of digoxin
15. Antiarrhythmic drug that is used to suppress digoxin-induced arrhythmias in some patients
Cardiac Glycosides & Congestive Heart Failure