96-15: Atrial tachyarrhythmias in patients after surgical CryoMaze ablation procedure

Abstract

Purpose of the study: The CryoMaze ablation procedure was developed as a surgical alternative to incisional treatment for atrial fibrillation. Incomplete lines can decrease the efficacy of the ablation procedure and can be proarrhythmic. The aim of this study is to determine incidence and mechanisms of atrial tachyarrhythmias occurring after surgical CryoMaze. We also studied the efficacy of completing surgical lines by RF catheter ablation to maintain sinus rhythm. Methods: Fourty-eight consecutive patients who required surgical CryoMaze ablation for persistent atrial fibrillation as an adjunct to a cardiac surgery were enrolled in the study. All patients had a 7-day ECG Holter 3 months after the surgical CryoMaze. Patients with documented paroxysmal or persistent atrial arrhythmias on the ECG Holter underwent an electrophysiological study with the right and left atria electroanatomical mapping using a CARTO3 navigation system. According to the protocol, patients in sinus rhythm were tested with incremental atrial pacing to induce atrial tachyarrhythmias after all gaps in surgical lines had been re-ablated using RF catheter ablation. If persistent atrial tachycardia was recorded at the beginning of the study, the tachycardia was mapped and ablated as the first step, which was followed by finalization of the surgical lines. All patients were followed-up for 24 months with repeated 7-day ECG Holters Summary of results: Thirteen (27%) patients had persistent and 12 (25%) patients had paroxysmal atrial tachyarrhythmia on the 7-day ECG Holter. Persistent arrhythmias were later confirmed during the electrophysiological study as atrial fibrillation in 5 patients, typical isthmus-dependent atrial flutter in 4 patients, 2 peri-mitral flutters, 1 roof dependent flutter and 1 focal atrial tachycardia from the inter-atrial septum. In patients with sinus rhythm in the beginning of the study, surgical lines were re-ablated in all patients. In 3 cases, incremental atrial pacing induced different focal atrial tachycardias after all surgical ablation lines had been finalized. All spontaneous and inducible arrhythmias were successfully mapped and ablated. Twenty-three out of 25 patients who underwent catheter ablation after surgical CryoMaze remained in sinus rhythm without antiarrhythmic medication during the 24-month follow-up. Conclusion: One quarter of patients after surgical CryoMaze suffer from persistent atrial tachyarrhythmias and another quarter have paroxysmal atrial arrhythmias. Catheter ablation of these tachyarrhythmias and finalization of surgical lines is effective approach to treat patients with documented atrial arrhythmias after surgical CryoMaze.