ECG Cardiac Pharmacology 4

Question 1

Flecainide is contraindicated in patients with structural heart disease primarily because it can cause which dangerous arrhythmia?

Accepted Answer

Proarrhythmia including fatal ventricular tachycardia

Answer

Complete AV block

Answer

Torsades de pointes only

Answer

Persistent sinus bradycardia

Question 2

A patient's ECG shows a rate of 42 bpm with a narrow QRS and no P waves. After atropine fails to increase the rate, which drug class would be next?

Accepted Answer

Catecholamine (dopamine or epinephrine infusion)

Answer

Class III antiarrhythmic

Answer

Calcium channel blocker

Answer

Digoxin loading dose

Question 3

Which drug's antiarrhythmic mechanism involves activation of acetylcholine-sensitive potassium current (IKACh) in the atria?

Accepted Answer

Adenosine

Answer

Amiodarone

Answer

Digoxin

Answer

Procainamide

Question 4

Dronedarone differs from amiodarone primarily in that it:

Accepted Answer

Lacks iodine moieties, reducing thyroid and pulmonary toxicity

Answer

Has a longer half-life requiring less frequent dosing

Answer

Is more effective in permanent atrial fibrillation

Answer

Can be safely used in patients with heart failure with reduced EF

Question 5

Digoxin increases vagal tone and inhibits the Na+/K+-ATPase pump. What is the net effect on the ventricular rate in atrial fibrillation?

Accepted Answer

Rate slows due to increased AV nodal refractoriness

Answer

Rate increases due to enhanced automaticity

Answer

Rate is unaffected; only rhythm is converted

Answer

Rate becomes irregular then regularizes

Question 6

Which antiarrhythmic is specifically indicated for Wolff-Parkinson-White syndrome with pre-excited atrial fibrillation?

Accepted Answer

Procainamide IV

Answer

Verapamil IV

Answer

Digoxin IV

Answer

Adenosine IV

Question 7

A patient develops a wide-complex tachycardia after starting a new antiarrhythmic. This drug-induced arrhythmia is known as:

Accepted Answer

Proarrhythmia

Answer

Torsades de pointes

Answer

Triggered automaticity

Answer

Reentrant tachycardia