A transcutaneous pacemaker is most likely an intervention for which dysrhythmia?

• A. Second-degree AV block, type II
• B. Atrial fibrillation
• C. Sinus tachycardia
• D. Ventricular fibrillation

Answer: (A)

Temporary external pacing is used when the heart’s conduction system can’t maintain an adequate rate, leading to clinically significant bradycardia with poor perfusion. In second-degree AV block, type II, the conduction below the AV node is unreliable and can progress to complete heart block, which markedly reduces heart rate and cardiac output. A transcutaneous pacemaker provides immediate, noninvasive pacing to stabilize the patient while a longer-term solution, like transvenous pacing or a permanent pacemaker, is arranged. This is the best choice because it directly supports a critically slow heart rate in a block that may deteriorate. Atrial fibrillation involves irregular, often rapid conduction; pacing doesn’t fix the rhythm and isn’t a primary treatment. Sinus tachycardia is a high heart rate due to stress or illness; pacing would not address the underlying cause and could worsen hemodynamics. Ventricular fibrillation is a chaotic rhythm requiring defibrillation and CPR, not pacing.