Introduction
Radiofrequency catheter ablation (RFCA) has been shown to be more
efficacious than drug therapy in restoring sinus rhythm (SR) in patients
with atrial fibrillation (AF). Compared to the other ablation
strategies, pulmonary vein isolation (PVI) is a more basic
strategy.1 Furthermore, a trigger ablation is one of
the strategies for AF ablation, which is effective for eliminating
AF.2 Isoproterenol (ISP) is often used to induce AF
triggers.3 In addition, defibrillation of induced AF
is performed to identify the site of the trigger of spontaneously
occurring AF. In those procedures, intracardiac defibrillation (IDF) is
often performed to restore SR during RFCA of AF.4
There have been many studies about cardioversion of AF, such as
regarding the relationship between the defibrillation threshold and
maintaining SR in patients without RFCA.5-11 On the
other hand, many other studies have pointed out the relationship between
AF recurrence after RFCA and the substrate, such as the left atrium (LA)
size and low voltage zones (LVZs). However, a few studies have shown the
relationship between the IDF threshold and recurrence of AF after RFCA.
Furthermore, there have been no studies to assess the relationship
between the IDF and LA substrate. This study aimed to examine the change
in the IDF threshold before and after RFCA for eliminating persistent AF
during the procedure. Additionally, we evaluated whether the IDF
threshold after RFCA was associated with the recurrence of AF and the AF
substrate after the ablation procedure in patients with persistent AF.