Electrophysiological Mechanism and Ablation Strategy for Macro-reentrant Biatrial Tachycardias Following Cox-Maze Procedures.

BACKGROUND: Different types of recurrent atrial tachycardias (ATs) following Cox-Maze procedures have been reported, while biatrial tachycardia (BiAT) have not been systematically analyzed.

OBJECTIVE: In the present study, we retrospectively investigated the electrophysiological characteristics of BiATs after Cox-Maze procedures by using an ultrahigh-density mapping system.

METHODS: Among a consecutive 76 patients who underwent catheter ablation of AT after Cox-Maze procedures, 12 BiATs were identified. High density activation mapping was performed in both left atrium (LA) and right atrium (RA) in combination with entrainment pacing to confirm the circuit.

RESULTS: We classified these BiATs into two groups:In group1(7 patients), the bidirectional block of MAZE linear lesions to prevent the macroreentrant AT was achieved , the posterior interatrial connections were involved in the circuit. In group 2 (5 patients), the bidirectional block of MAZE linear lesions was not blocked and the most common gap was located at the end of of the linear lesion near the annulus. In Group 1, all the ATs were terminated by targeting the corresponding LA end of the posterior interatrial connections.In Group 2, the ATs were terminated by targeting the gap near the annulus.

CONCLUSIONS: The optimal ablation strategy for BiATs after MAZE procedure should be based on the detailed demonstration of the circuit by high density mapping.