Ablation of atrial tachycardia in the setting of prior mitral valve surgery.

BACKGROUND Data regarding catheter ablation of post-surgical atrial tachycardia occurring after mitral valve surgery are scarce. Through a search of the literature, this study aimed to assess the feasibility of catheter ablation and the characteristics of atrial arrhythmias ablated in these patients. METHODS Studies assessing the main procedure parameters and the electrophysiologic findings of the investigated atrial tachycardia were selected. The electrophysiologic mechanism (focal vs. reentrant arrhythmias), site of arrhythmia origin (left atrium vs. right atrium) and their anatomic correlation with specific surgical access and/or prior Cox-Maze IV procedure were all addressed. RESULTS Eleven studies including 206 patients undergoing catheter ablation of 297 post-surgical arrhythmia morphologies occurring after mitral valve surgery were considered. Major complications were observed in 2 patients only (0.9%). Restoration of sinus rhythm was achieved in 96% of patients. Macro-reentrant arrhythmia was mostly observed (90.4%) with a non-negligible proportion of focal arrhythmia (9.6%). Left-sided arrhythmia was common (54.4%,) but cavotricuspid isthmus-dependent arrhythmia was frequently reported (33%). Although specific atriotomies showed trends towards peculiar locations of the investigated arrhythmia, Cox-Maze IV procedure was the only independent predictor for left-sided arrhythmia (OR=17.3; 95% CI 7.2-41.2; p<0.0001). CONCLUSIONS Catheter ablation of post-surgical arrhythmia occurring after mitral valve surgery is feasible, and, in this setting, the vast majority of the arrhythmia morphologies are based on macroreentry and in about one third of cases show cavotricuspid isthmus-dependent arrhythmia. Prior Cox-Maze-IV associated with mitral valve surgery is an independent predictor of left-sided arrhythmia possibly due to non-transmural surgical lesions.