Relationship between electrical gap after Maze procedure and atrial
arrhythmia and ablation outcome after cardiac surgery and concomitant
Introduction: There are few reports of the characteristics, mechanisms,
and outcomes of atrial tachycardia (AT) and atrial fibrillation (AF)
ablation after cardiac surgery and concomitant Maze procedures. This
study investigated the mechanisms and long-term outcomes of AT and AF
ablation after various Maze procedures, especially we examined in detail
whether the arrhythmia after Maze procedure was due to gap or not.
Methods and Results: We analyzed 37 consecutive cases with AT and AF
after cardiac surgery and Maze procedure between 2007 and 2019.
Fifty-nine atrial arrythmias were induced in 37 consecutive cases, and
49 of those atrial arrythmias were mappable ATs. Forty-two ATs was
related to the Maze procedure in the 49 mappable ATs (87.5%). All 37
consecutive cases had residual electrical conductions (gaps) in the Maze
lines (88 gaps; 2.4±1.2 gaps/patient). Forty-two of 88 gaps (47.7%)
were associated with gap-related ATs. The most common gap-related ATs in
this study were peri-mitral atrial flutter in 22 cases. The median
follow-up period after ablation was 3.6±3.2 years (median, 2.1 years;
interquartile range, 0.89-6.84). The Kaplan-Meier analysis of freedom
from recurrent atrial arrhythmia after Maze procedure was 79.9% at
1-year follow up and 69.3% at 4-year follow up. Conclusions: Reentry
was the main mechanism of AT after cardiac surgery and concomitant
various Maze procedures, and AT were largely related to the gap in the
Maze line between mitral valve anulus and pulmonary vein isolation line.
Catheter ablation of AT after various Maze procedures seemed to be
effective and safe during long-term follow-up.