Medical Pharmacology Practice Questions: Antiarrhythmic Drugs

Causative factor(s) of arrhythmias include(s):
1. Abnormal cardiac action potential propagation
2. Abnormal cardiac pacemaker function
3. Both
4. Neither
Which one(s) of the following pharmacologic therapeutic objectives for managing arrhythmias is/are correct?
1. To reduce non-SA nodal i.e. ectopic pacemaker cell activity.
2. To disable "Circus" or cyclic cardiac conduction in reentry by changing myocardial conduction or refractoriness properties.
3. Both
4. Neither
The principal pharmacologic mechanism(s) underlying therapeutic effectiveness of antiarrhythmic agents include(s):
1. Cardiac sodium-channel block
2. Increase in sympathetic autonomic cardiac effects
3. Ca2+ channel blockade
4. Shortening of the effective refractory. (ERP)
5. A & B
6. A&C
7. D only
8. A, B, & C
Antiarrhythmic agents exhibit is greater effects on cardiac conduction inexcitability and depolarize tissue compared to normally polarized cardiac tissue
1. . True
2. False
Concerning effective calcium or sodium channel antiarrhythmic drug blockade, effective agents tend to bind principally to "rested "channels.
1. True
2. False
Cardiac cells exhibiting pathologic, abnormal automaticity (cellular membrane potential drifts towards threshold, a.k.a. phase 4) may be reduced by which one(s) of the following?
1. Blockade of sodium channels
2. Blockade of calcium channels
3. Both
4. Neither
Mechanism(s) which may decrease the rate of myocardial action potential propagation includes/include:
1. Lengthening of channel recovery time, thus increasing the effective refractory. (ERP)
2. Increasing the number of available unblocked channels
3. Both
4. Neither
Circumstances that allow transition of an antiarrhythmic drug effect to a proarrhythmic, increase in arrhythmias includes/include:
1. An elevation in heart rate
2. Acidosis
3. Ischemia
4. Hypokalemia
5. A & B
6. D only
7. A, B & C
Even at high doses antiarrhythmic drugs do not cause drug-induced arrhythmias.
1. True
2. False
One effect of ß-adrenergic receptor antagonists is to reduce the slope of phase 4 depolarization.
1. True
2. False