Quiz 23: Treatment of Cardiac Arrhythmias

Which of the following drug categories is NOT used to treat cardiac arrhythmias? A)Sodium channel blockers B)Chloride channel blockers C)Beta blockers D)Calcium channel blockers E)Drugs that prolong cardiac repolarization

Beta blockers are effective in treating certain cardiac arrhythmias because they _____ the excitatory effects of ______ on the heart. A)increase;acetylcholine B)decrease;acetylcholine C)increase;catecholamines (epinephrine and norepinephrine) D)decrease;catecholamines (epinephrine and norepinephrine) E)increase;beta interferons

An antiarrhythmic drug that prolongs the effective refractory period of the cardiac action potential: A)will speed up repolarization of cardiac muscle cells. B)will generally increase heart rate. C)will decrease the time interval between cardiac action potentials. D)all of the above E)none of the above

Calcium channel blockers are useful in treating certain cardiac arrhythmias because they: A)decrease the rate of discharge of the sinoatrial (SA)node. B)increase conduction velocity through the atrioventricular (AV)node. C)block the effects of catecholamines (epinephrine,norepinephrine)on cardiac tissues. D)inhibit the sodium's ability to excite cardiac membranes. E)none of the above;calcium channel blockers are not used to treat arrhythmias.

While attempting to control one type of arrhythmia,antiarrhythmic drugs can exert "proarrhythmic" effects,which are indicated by: A)a delay of 4 to 6 weeks before these drugs become effective. B)common musculoskeletal abnormalities such as skeletal muscle fasciculations. C)their ability to aggravate or initiate other cardiac rhythm abnormalities. D)their ability to aggravate the proton pump in the stomach,resulting in gastric ulcers. E)their ability to increase body temperature and cause fever.

Depending on the dose and route of administration,lidocaine (Xylocaine)and similar drugs can be used as local anesthetics or cardiac antiarrhythmic drugs because they affect the excitability of _____ ion channels. A)sodium B)potassium C)chloride D)calcium E)magnesium