Cardiac Medicine Certification (CMC) Practice Exam

What drug classifications are typically contraindicated in patients with second-degree AV block?

1. Diuretics and anticoagulants

2. Calcium channel blockers and beta-blockers

3. NSAIDs and corticosteroids

4. ACE inhibitors and ARBs

The correct answer is: Calcium channel blockers and beta-blockers

In patients with second-degree atrioventricular (AV) block, it is important to avoid specific drug classifications that can further impair cardiac conduction. Calcium channel blockers and beta-blockers are typically contraindicated in these patients because both classifications can have negative effects on heart rate and AV conduction. Calcium channel blockers, particularly non-dihydropyridines like verapamil and diltiazem, decrease the rate of conduction through the AV node. This is problematic in patients with second-degree AV block, where there is already an existing issue with electrical conduction between the atria and ventricles. Similarly, beta-blockers also slow down heart rate and can worsen the conduction delay, potentially leading to more severe blocks or even complete heart block. The other drug classifications mentioned do not have the same impact on AV conduction. Diuretics and anticoagulants primarily target fluid balance and blood clots, respectively, rather than directly influencing heart rhythm. NSAIDs and corticosteroids primarily offer anti-inflammatory effects and do not significantly affect cardiac conduction pathways. ACE inhibitors and angiotensin receptor blockers (ARBs) are primarily used for managing hypertension and heart failure, and they do not directly interact with AV nodal conduction. Thus, they are generally not contraind