Effect of electrophysiological mapping on non-transmural annulus ablation and atrial fibrillation recurrence prediction after 6 months of Cox-Maze IV procedure

Abstract

Objective: The objective of this study was to observe the safety and efficacy of electrophysiological mapping following the Cox-Maze IV procedure and to investigate whether a correlation exists between recurrence of atrial fibrillation (AF) with the completeness of bidirectional electrical isolation and the inducibility of AF immediately after the Cox-Maze IV procedure.

Methods: Totally, 80 consecutive patients who suffered from aortic valve or mitral valve disease and persistent AF were randomly enrolled into the control group and electrophysiological mapping following the Cox-Maze IV group (Electrophysio-Maze group). In the Electrophysio-Maze group, patients underwent concomitant Cox-Maze procedure and following electrophysiological mapping of ablation lines in mitral isthmus, left atrial "box," and tricuspid annulus. If the bidirectional electrical isolation of tricuspid annulus ablation line is incomplete, whether to implement supplementary ablation will be independently decided by the operator. Before and after the Cox-Maze IV procedure, AF induction was performed. All patients in both groups were continuously followed-up and underwent electrocardiogram Holter monitoring after 6 months.

Results: In total, 42 Electrophysio-Maze patients and 38 controls were enrolled. Compared with patients in the control group, there were shorter hospital stay, better cardiac remodeling changes, and higher relief from AF during the follow-up period of 6 months in the Electrophysio-Maze group. Within the Electrophysio-Maze group, the rate of incomplete the bidirectional electrical isolation of "box" ablation lines was zero, and the rate of incomplete bidirectional electrical isolation of mitral isthmus ablation line or tricuspid annulus ablation line was 23.8%. After two cases of successful complementary ablation on the tricuspid annulus ablation line, the final incomplete bidirectional electrical isolation of annulus ablation lines was 19.0%. There were correlations between late AF recurrence after 6 months with incomplete bidirectional electrical isolation of annulus ablation lines and AF induction immediately after the Cox-Maze IV procedure.

Conclusion: Electrophysiological mapping following the Cox-Maze procedure is safe and effective. Electrophysiological mapping in the Cox-Maze procedure can find out the non-transmural annulus ablation lines by assessing the completeness of bidirectional electrical isolation of ablation lines, guide supplementary ablation, and predict AF recurrence after 6 months.

Keywords: Cox-Maze IV; ablation lines; electrical isolation; mapping; recurrence; surgery.

FIGURE 1

Induction of atrial fibrillation (AF). (A) Image of programmed stimulation at high right atrial for induction of atrial fibrillation (post surgery). (B) AF induced by the 190 ms cycle stimulation before Cox-Maze IV. (C) After Cox-Maze IV, the 190 ms cycle stimulation failed to induce AF again. (D) After Cox-Maze IV, the 170 ms cycle stimulation could not induce AF; and (E) After Cox-Maze IV, the 150 ms cycle stimulation could not induce AF.

FIGURE 2

Ablation line mapping of mitral isthmus. (A) Coronary sinus catheter mapping of mitral isthmus ablation line. (B) Distal (CS1-2) delay during proximal (CS9-10) pacing of coronary sinus catheter (more than 120 ms). (C) Proximal delay during distal pacing of coronary sinus catheter (more than 120 ms).

FIGURE 3

Mapping of left atrial “box” lesion. (A) Coronary sinus catheter mapping of left atrial “box” lesion. (B) Inner-box polar could not sense the outer potential under sinus rhythm. (C) Pacing of inner-box polar could not capture or disturb the sinus rhythm of the outer atrium.

FIGURE 4

Mapping of tricuspid valve annular ablation line. (A) Coronary sinus catheter mapping of tricuspid valve annular ablation line. (B) Distal polar in free side wall of the right atrium (CS1-2) delay during proximal polar near the anterior atrial sulcus (CS9-10) pacing of coronary sinus catheter (more than 120 ms). (C) Proximal delay during distal pacing of coronary sinus catheter (more than 120 ms).