If there are infrequent PVCs what mapping strategy can be used to locate the origin?

• A. Activation mapping
• B. Voltage mapping
• C. Correlation mapping
• D. Pace mapping

Answer: (D)

When the ectopic beats are infrequent, you can’t rely on capturing and timing the spontaneous PVC across the chamber to map its origin. That’s where pace mapping shines. You pace from many different sites in the ventricle during normal rhythm and compare the resulting paced QRS morphology to the patient’s clinical PVC morphology across multiple ECG leads. The site that produces the closest match is the most likely origin of the PVC. In other words, you use deliberate pacing to recreate the same QRS pattern, then lock onto the site that best reproduces it.

Activation mapping depends on the actual spontaneous PVC to time activation at many points, which isn’t feasible with rare PVCs. Voltage mapping shows scar or substrate rather than pinpointing the PVC origin. Correlation-based approaches aren’t the standard method for localizing the ectopic focus. So pace mapping is the practical choice when PVCs don’t occur often enough to map their activation sequence.