Incomplete ablation as a mechanism of atrial fibrillation recurrence and atrial tachycardia development after maze procedure.

OBJECTIVE

Atrial tachyarrhythmias are the most frequent complication after the maze procedure. We examined the mechanism of atrial tachyarrhythmias in association with the ablation energy and technique used at each lesion and by the findings of postoperative electrophysiological study.

METHODS

Four-hundred fifty-three patients who underwent the maze procedure with biatrial incisions and bilateral pulmonary vein (PV) isolation were examined for the incidence and mechanism of recurrence of atrial fibrillation (AF) and development of atrial tachycardia (AT). PV isolation was performed by radiofrequency (RF) ablation, cryothermia, or cut-and-sew technique. The atrioventricular isthmi and the coronary sinus (CS) were ablated by RF, cryothermia, or a combination of these.

RESULTS

Of 443 patients who survived surgery (98%), 54 patients (12.2%) had recurrent AF and 36 patients (8.1%) developed AT during the median of 28 months (interquartile range, 3-75) postoperatively. Multivariate logistic regression analysis showed preoperative left atrial dimension and nonperformance of intraoperative PV pacing were the independent predictors for AF recurrence. Electrophysiologic study in patients with AT demonstrated incomplete ablation in 24 patients (67%), most frequently at the CS in 16 patients (67%), and non-PV focal activations in 16 patients (44%). Preoperative New York Heart Association functional class of 1 and nonperformance of additional epicardial ablation of the CS were the independent predictors for postoperative AT development.

CONCLUSIONS

Incomplete ablation is a cause of AF recurrence and AT development after the maze procedure. Intraoperative PV pacing prevents AF recurrence and additional epicardial CS ablation prevents AT development.