Fehmi Keçe

Chapter 6 138 6.4.8 Complications in time-to-isolation dependent ablation A multicenter comparison of 352 patients undergoing an additional ablation of 120s after time-to-isolation with both a double (152 patients) and single (59 patients) 240s application found 3.7%, 7.9% and 8.5% complications, respectively(3). However, numbers were mainly driven by remote complications (groin and respiratory tract infections: 0.6%, 1.3% and 5.1%), while phrenic nerve palsy was present in 2.0%, 5.7% and 3.4%. In the study of Aryana et al. comparing a protocol guided by time-to-isolation (n=355) versus a conventional group (n=400), adverse events were similar at 2.0% and 2.7%, with a numerically lower phrenic nerve palsy incidence of 0.6% in the time-to-isolation group vs. 1.2 in the control group (p=0.33)(18). The randomized trial of 140 patients reported 8% complications with 3.6% phrenic nerve palsy and no differences between the groups (19). Our results are comparable to these numbers and were not significantly different between the groups. 6.4.9 Limitations This is a small-size single-center randomized study. The study was powered to detect differences in reconnection/DC and not to detect significant differences in complications and recurrence rates. Therefore, a substantial conclusion cannot be drawn regarding outcome and complications. In this study only ablation duration and not contact force and ablation energy were optimized, as contact force cannot be measured by the current technology and ablation energy (balloon gas flow) cannot be adjusted by the operator. Indirect measurements for balloon occlusion, such as fluoroscopic contrast stasis or intracardiac echo doppler measurements were not routinely documented in this study. Due to the small number of patients these factors may have biased the results. In addition, dormant conduction was used to reveal incomplete pulmonary vein isolation, which is only a surrogate for durable PV isolation. In this study the 90s dosing protocol was the least successful with a significant higher number of reconnection/DC. Given the low number of patients in each group, it is possible that there is no significant differences in reconnection/DC between the 120 and 150s group. During follow up only 24-h Holter monitoring was used, longer rhythm monitoring could have detected more AF-episodes. However, we consequently encouraged patients to seek healthcare support for additional ECG recordings if symptoms occurred.