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.