During pace mapping when VT is non-inducible, pacing is performed during which rhythm?

During pace mapping when VT is non-inducible, pacing is performed during which rhythm?

• A. Sinus rhythm
• B. Atrial paced rhythm
• C. Ventricular paced rhythm
• D. Atrial fibrillation rhythm

Answer: (A)

Pace mapping aims to reproduce the VT QRS morphology by pacing from different ventricular sites while the heart is in a stable rhythm, so you can identify the region that best matches the VT. When VT is non-inducible, you can’t map during the actual VT, so you rely on pacing during a normal, steady rhythm to generate a consistent QRS pattern from each site. Sinus rhythm provides that stable activation sequence, allowing meaningful comparison between the paced QRS and the VT morphology. If you tried pacing during atrial fibrillation or an irregular or artificially paced ventricular rhythm, the resulting QRS patterns would be inconsistent or influenced by the irregular activation or pacing mechanics, making it hard to identify the correct substrate. By using sinus rhythm, the site that yields a paced QRS that most closely matches the VT QRS is likely a key exit or circuit area, guiding targeted ablation.

Pace mapping aims to reproduce the VT QRS morphology by pacing from different ventricular sites while the heart is in a stable rhythm, so you can identify the region that best matches the VT. When VT is non-inducible, you can’t map during the actual VT, so you rely on pacing during a normal, steady rhythm to generate a consistent QRS pattern from each site. Sinus rhythm provides that stable activation sequence, allowing meaningful comparison between the paced QRS and the VT morphology. If you tried pacing during atrial fibrillation or an irregular or artificially paced ventricular rhythm, the resulting QRS patterns would be inconsistent or influenced by the irregular activation or pacing mechanics, making it hard to identify the correct substrate. By using sinus rhythm, the site that yields a paced QRS that most closely matches the VT QRS is likely a key exit or circuit area, guiding targeted ablation.