Results
The baseline characteristics of patients are summarized in Table 1. All of the study patients were male, and the mean age was 50±17 years. All of the patients had paroxysmal AF. Two patients had a prior history of anterior myocardial infarction, and one patient was diagnosed with idiopathic ventricular fibrillation and had an implantable cardioverter-defibrillator. The remaining four patients have no underlying heart disease. The mean LA diameter was 35.6±5.0 mm, and the mean left ventricular ejection fraction was 60±12% by echocardiography. Two patients (Case 1 and 2) underwent a prior AF ablation procedure. In their previous procedures, ATP injection did not induce AF in Case 1, and in Case 2, ATP was administered during ongoing AF.