Key result
An additional pacing maneuver from the left lateral ridge up to the roof unmasked epicardial conduction in 32% of patients, and targeting these conductions achieved total mitral isthmus block in 94%.
Why the study?
Achieving mitral isthmus block remains challenging and epicardial conduction could play a key role in peri-mitral atrial tachycardia recurrence.
Does pacing from the left lateral ridge to unmask and target epicardial conduction improve the achievement of total mitral isthmus block in patients undergoing ablation for persistent atrial fibrillation?
Observational (n=50)
Does pacing from the left lateral ridge to unmask and target epicardial conduction improve the achievement of total mitral isthmus block in patients undergoing ablation for persistent atrial fibrillation?
An additional pacing maneuver from the left lateral ridge can unmask epicardial conduction in nearly a third of patients after initial mitral isthmus block, and targeted ablation of these conductions achieves total block in 94% of cases.
Masked epicardial conduction may underlie peri-mitral tachycardia recurrence; leaves open whether targeted ablation improves outcomes.
BACKGROUND: Achieving mitral isthmus (MI) block remains a challenge. Epicardial conduction (EC) could play a key role in peri-mitral atrial tachycardia recurrence. OBJECTIVE: The aims of this study were to evaluate the prevalence of masked EC in patients with MI block and to assess the feasibility of targeting EC by radiofrequency ablation. METHODS: 50 consecutive patients who underwent ablation for persistent atrial fibrillation with successful pulmonary vein isolation, roof line block, and MI block were included. After completion of MI block using a systematic strategy comprising up to 3 consecutive steps, patients underwent pacing from the left lateral ridge (LLR) up to the roof to unmask EC. Isolation by radiofrequency ablation of EC was evaluated in patients with masked EC. Presence of conduction block across the ablation line was confirmed using standard pacing maneuvers from the left atrial appendage and along the mitral line in all 50 patients. RESULTS: Pacing from the LLR up to the roof unmasked EC in 16 of 50 patients (32%). Among these patients, additional ablation was performed to isolate EC with a success rate of 81.3% (13/16). Overall total isthmus block was observed in 47/50 patients (94%). No complications were reported. CONCLUSION: After MI block, an additional pacing maneuver from the LLR up to the roof unmasked EC in 32% of patients. Targeting these conductions achieved total MI block in 94% of patients.
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Mechulan et al. (2025) conducted an observational in Persistent atrial fibrillation (n=50). Pacing from the left lateral ridge up to the roof and targeted radiofrequency ablation was evaluated on Total mitral isthmus block. An additional pacing maneuver from the left lateral ridge up to the roof unmasked epicardial conduction in 32% of patients, and targeting these conductions achieved total mitral isthmus block in 94%.
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