If an SVT terminates without atrial activation upon cessation of ventricular pacing, the pacing maneuver excludes which tachycardia?

If an SVT terminates without atrial activation upon cessation of ventricular pacing, the pacing maneuver excludes which tachycardia?

• A. AT
• B. VT
• C. Atrial flutter
• D. AVNRT

Answer: (A)

The key idea is how ventricular overdrive pacing interacts with the tachycardia and what happens to atrial activity after the last paced ventricle. If the tachycardia stops and there is no atrial activation immediately after the pacing ends, there is no retrograde conduction from ventricle to atrium. That means the atria are not participating in driving or reactivating the rhythm in this scenario. An atrial tachycardia would rely on atrial tissue as the driver, so you would expect atrial activity to resume or be evident after pacing stops. The absence of an atrial response thus argues against atrial tachycardia being the culprit.

The key idea is how ventricular overdrive pacing interacts with the tachycardia and what happens to atrial activity after the last paced ventricle. If the tachycardia stops and there is no atrial activation immediately after the pacing ends, there is no retrograde conduction from ventricle to atrium. That means the atria are not participating in driving or reactivating the rhythm in this scenario. An atrial tachycardia would rely on atrial tissue as the driver, so you would expect atrial activity to resume or be evident after pacing stops. The absence of an atrial response thus argues against atrial tachycardia being the culprit.