Methods
We enrolled 44 consecutive HD patients who underwent CA for AF in Shonan Kamakura General Hospital from August 2011 to May 2019. The study protocol was approved by Mirai Medical Center Ethical Committee (TGE01468-024), and the study was conducted according to the tenets of the Declaration of Helsinki. This study enrolled not only patients with PAF but also patients with persistent atrial fibrillation (PeAF) and long-standing persistent atrial fibrillation (LSAF).
The selection of CA method was based on the timing of the introduction of the CBA and Pulmonary vein(PV) anatomies. Before the introduction of the CBA, all patients underwent pulmonary vein isolation (PVI) using RFA. After the introduction of the CBA in 2016, 23 patients underwent PVI with CBA, while three patients underwent PVI with RFA because of a large PV (Figure 1).
In this study, we compared patients who received CBA (CBA group) and those who received RFA (RFA group). The primary endpoint was defined as freedom from a composite outcome of a documented recurrence of atrial tachyarrhythmia (ATA) (lasting more than 30 seconds) or a prescription of an AAD (class I or III). This primary endpoint was analyzed at one year after the first CA. The secondary endpoint was defined as freedom from the documented recurrence of any ATA (lasting more than 30 seconds) at one year after the first CA. Episodes of ATA within the first 3-month after the procedure were not considered instances of recurrence (blanking period). The use of AAD after blanking period was based on the physician’s discretion considering to patient’s symptoms such as palpitation with or without a documented ATA. Within the blanking period, recurrent arrhythmias could be managed with AAD and cardioversion without penalty with regard to the primary efficacy and secondary end point. The procedure time and complications were also evaluated. The complications were defined as unexpected events which required intervention or prolonged hospital stays beyond the scheduled period.
All AADs were discontinued for at least three days before CA. All patients received warfarin for at least three weeks, and the internationalized normalized ratio for blood coagulation was checked before ablation. A nasogastric thermometer (Esophastar, JAPAN LIFELINE, Japan) was inserted to measure the esophageal temperature during ablation. All procedures during ablation were performed under sedation with intravenous propofol.
An activated clotting time of 300–350 seconds was maintained with a continuous infusion of heparin during the procedure. Isoproterenol (5–10 µg) was injected intravenously after the PVI. If sustained or non-sustained AF was reproducibly induced from non-PV foci, they were additionally ablated.5 When non-PV foci were located in the superior vena cava (SVC), the SVC was electrically isolated.6
Dormant PV conduction was intended to be induced with adenosine triphosphate (20 mg) under isoproterenol infusion. If dormant PV conduction was captured, an additional CBA or touch-up ablation was performed.