IBHRE Pharmacology and Drug Therapy 3

Question 1

Procainamide's active metabolite NAPA primarily exhibits which class of antiarrhythmic activity?

Accepted Answer

Class III

Answer

NAPA (N-acetylprocainamide) is a Class III antiarrhythmic that blocks IKr, prolonging the action potential duration and QT interval.

Question 2

What INR range is targeted for warfarin anticoagulation in atrial fibrillation for stroke prevention?

Accepted Answer

2.0–3.0

Answer

The target INR for stroke prevention with warfarin in non-valvular atrial fibrillation is 2.0–3.0, balancing thromboembolic and bleeding risk.

Question 3

Which direct oral anticoagulant (DOAC) acts as a direct thrombin inhibitor rather than a factor Xa inhibitor?

Accepted Answer

Dabigatran

Answer

Dabigatran directly inhibits thrombin (factor IIa), whereas rivaroxaban, apixaban, and edoxaban are all factor Xa inhibitors.

Question 4

Lidocaine (Class IB) is most effective for treating which type of arrhythmia?

Accepted Answer

Ventricular tachycardia and fibrillation

Answer

Lidocaine preferentially suppresses ischemic myocardium and is used for ventricular tachycardia and fibrillation, particularly in the setting of acute myocardial infarction.

Question 5

Verapamil's mechanism for treating AV nodal-dependent tachycardias is primarily?

Accepted Answer

L-type calcium channel blockade in the AV node

Answer

Verapamil blocks L-type calcium channels in the AV node, slowing conduction and prolonging the AV nodal refractory period to terminate or prevent reentrant tachycardias.

IBHRE - International Board of Heart Rhythm Examiners Practice Test

IBHRE - International Board of Heart Rhythm Examiners Practice Test

IBHRE Pharmacology and Drug Therapy 3