Question 1

An antiarrhythmic drug that prolongs the effective refractory period of the cardiac action potential:&#10;A)will speed up repolarization of cardiac muscle cells.&#10;B)will generally increase heart rate.&#10;C)will decrease the time interval between cardiac action potentials.&#10;D)all of the above&#10;E)none of the above

Accepted Answer

An antiarrhythmic drug that prolongs the effective refractory period will slow down repolarization, generally decrease heart rate, and increase the time interval between cardiac action potentials, making none of the options correct.

Question 2

Beta blockers are effective in treating certain cardiac arrhythmias because they _____ the excitatory effects of ______ on the heart.&#10;A)increase;acetylcholine&#10;B)decrease;acetylcholine&#10;C)increase;catecholamines (epinephrine and norepinephrine)&#10;D)decrease;catecholamines (epinephrine and norepinephrine)&#10;E)increase;beta interferons

Accepted Answer

Beta blockers work by decreasing the effects of catecholamines (epinephrine and norepinephrine) on the heart, which can cause increased heart rate and irregular heart rhythms. This helps to slow down the heart rate and prevent arrhythmias.

Question 3

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

sodium

Accepted Answer

Lidocaine and similar drugs affect the excitability of sodium ion channels, which are important in the generation and propagation of action potentials in neurons and cardiac cells. By blocking sodium channels, these drugs can effectively block pain signals in local anesthesia or prevent abnormal heart rhythms.

Question 4

Calcium channel blockers are useful in treating certain cardiac arrhythmias because they:&#10;A)decrease the rate of discharge of the sinoatrial (SA)node.&#10;B)increase conduction velocity through the atrioventricular (AV)node.&#10;C)block the effects of catecholamines (epinephrine,norepinephrine)on cardiac tissues.&#10;D)inhibit the sodium's ability to excite cardiac membranes.&#10;E)none of the above;calcium channel blockers are not used to treat arrhythmias.

Accepted Answer

Calcium channel blockers decrease the rate of discharge of the sinoatrial (SA) node, which helps in treating certain cardiac arrhythmias by slowing down the heart rate.

Question 5

Which of the following drug categories is NOT used to treat cardiac arrhythmias?&#10;A)Sodium channel blockers&#10;B)Chloride channel blockers&#10;C)Beta blockers&#10;D)Calcium channel blockers&#10;E)Drugs that prolong cardiac repolarization

Accepted Answer

Chloride channel blockers are not used to treat cardiac arrhythmias. Other drug categories, such as sodium channel blockers, beta blockers, calcium channel blockers, and drugs that prolong cardiac repolarization, are commonly used to treat cardiac arrhythmias.

Question 6

While attempting to control one type of arrhythmia,antiarrhythmic drugs can exert &#34;proarrhythmic&#34; effects,which are indicated by:&#10;A)a delay of 4 to 6 weeks before these drugs become effective.&#10;B)common musculoskeletal abnormalities such as skeletal muscle fasciculations.&#10;C)their ability to aggravate or initiate other cardiac rhythm abnormalities.&#10;D)their ability to aggravate the proton pump in the stomach,resulting in gastric ulcers.&#10;E)their ability to increase body temperature and cause fever.

Accepted Answer

Proarrhythmic effects refer to the ability of antiarrhythmic drugs to worsen or trigger other types of arrhythmia in addition to the one they are intended to treat. This is a well-known phenomenon in cardiology and is a significant concern when prescribing these drugs. Delay in effectiveness is not related to proarrhythmic effects, and musculoskeletal abnormalities, increased body temperature, and gastric ulcers are not typically associated with antiarrhythmic medication use.

Deck 23: Treatment of Cardiac Arrhythmias