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Purpose: Myocardial thickness is particularly thick at the ridge between the left pulmonary vein (PV) and the left atrial appendage (LAA) by dissection. We investigated whether the atrial fibrillation (AF) ablation outcome was influenced by altering ablation strategies according to the thickness of the PV-LAA ridge using preprocedural multidetector computed tomography (MDCT). Methods: Patients with AF scheduled for extensive encircling circumferential pulmonary vein isolation (EEPVI) (110 pts) were divided into two groups. In the nonmodulation group (32 pts), EEPVI lines were created using a 3.5-mm tip irrigated catheter at a maximum power of 30 W for 15–20 s at each site. In the modulation group (78 pts), ablation was extended (30–40 s) at the PV-LAA ridge if its thickness was >4.0 mm on MDCT. Results: In the modulation group, extended ablation at the PV-LAA ridge was observed in 37 pts. During 25±9 months of follow-up, the recurrence was significantly less in the modulation group (10% vs. 28%, p=0.018). Logistic regression analysis demonstrated that modifications in the ablation time and LA volume index were independent predictors of arrhythmia-free recovery after ablation. Conclusion: Recurrence following EEPVI could be reduced by modifications in the ablation time at the PV-LAA ridge.

Background: Indication of ablation has been expanded to include chronic atrial fibrillation (CAF) for enabling high degree of sinus rhythm maintenance. We have encountered patients undergoing pacemaker implantation, in whom sick sinus syndrome became clinically evident after ablation. The study aims to investigate whether underling sinus node dysfunction (SND) during CAF can be predicted before deciding the indication for ablation. Methods and Results: Sixty consecutive patients with CAF who underwent ablation between January to December 2010 were enrolled in the study. Nocturnal polysomnography as well as echocardiography was performed for all patients before ablation. We used the double Lasso catheter and electro anatomical mapping guided extensive encircling pulmonary vein isolation (EEPVI). We performed electrophysiological studies after EEPVI, and SND was defined as corrected SN recovery time of ≥550 ms. SND was detected in 26 (43%) patients (SND group); the other patients showed normal sinus node function (NSN group). The apnea/hypopnea index (AHI) was significantly greater in the SND group than in the NSN group (25.7±13 vs 15.8±10, P=0.0022). On multivariate analysis, sleep apnea syndrome (SAS) was an independent predictor of SND after ablation for CAF. Conclusion: This study suggested that underlying SND in CAF patients can be predicted by evaluating SAS before ablation.