Advanced Cardiovascular Life Support (ACLS) Practice Exam

Which medication is contraindicated in patients with heart block?

1. Atropine

2. Adrenaline

3. Adenosine

4. Amiodarone

The correct answer is: Atropine

Atropine is indicated in the management of bradycardia and can be effective in increasing heart rate by blocking the effects of the vagus nerve on the heart. However, its use is contraindicated in patients with certain types of heart block, specifically second-degree type II and third-degree heart block, because it may aggravate the condition or lead to further deterioration in heart rhythm. In these cases, the heart's electrical signals are already impaired, and atropine's ability to increase heart rate may not be effective. In contrast, other medications listed, like adrenaline (epinephrine), adenosine, and amiodarone, have different mechanisms and indications. Adrenaline is often used during cardiac arrest situations or for anaphylaxis and can help improve perfusion in emergencies. Adenosine is typically used to treat certain supraventricular tachycardias by temporarily blocking the conduction through the atrioventricular (AV) node. Amiodarone is an antiarrhythmic used for various tachyarrhythmias and does not have the same contraindications related to heart block as atropine does. Therefore, recognizing the specific indications and contraindications associated with each medication is crucial for appropriate patient management.