Study population
Our study consisted of 560 consecutive patients (419 males and 141 females, mean age ± standard deviation = 67.2 ± 9.1 years) with non-paroxysmal AF who underwent initial MI ablation in the Kimitsu Central Hospital. The study duration was from January 2012 to September 2019; however, EIVOM has been started in our institute since February 2015. EIVOM and RF ablation were performed in 176 patients (EIVOM/RF group) with the amenable VOM. In the remaining 384 patients, MI block line was created via only RF because the patients underwent catheter ablation before then, or they lacked the amenable VOM. All patients provided informed consent before the procedure. This study was conducted according to the protocol that was approved by the Ethic Committee at the Kimitsu Central Hospital.