Background-Identification of critical atrial substrates in patients with nonparoxysmal atrial fibrillation (AF) failing to respond to pulmonary vein isolation is important. This study investigated the signal characteristics, substrate nature, and ablation results of rotors during AF. Methods and Results-In total, 53 patients (age=55±8), 31 with persistent AF and 22 with long-lasting AF, underwent pulmonary vein isolation and substrate modification of complex fractionated atrial electrograms. Small-radius-reentrant rotors were identified from signal analyses of the dominant frequency and fractionation interval and nonlinear analyses (newly developed, beat-to-beat nonlinear measurement of the repetitiveness of the electrogram morphology >6 seconds). In 15% of the patients, activation maps demonstrated occurrences of rotor-like small-radius reentrant circuits (n=9; 1.1 per patient; cycle length=110±21 ms; diameter=11±6 mm) with fibrillation occurring outside these areas. Rotors were identified by conventional point-by-point mapping and signal analyses and were subsequently eradicated by catheter ablation in these patients. Persistent AF for <1 year, a smaller left atrial size, substrates with higher mean voltages and shorter total activation durations predicted a higher incidence of rotors (all P<0.05). In the multivariable model, areas of reentrant circuits exhibited a higher dominant frequency, kurtosis, and higher degree of a beat-to-beat electrogram similarity than areas without or outside the rotors (all P<0.05). Conclusions-Rotor-like re-entry with fibrillatory conduction was found in a limited number of patients with nonparoxysmal AF after pulmonary vein isolation. Those areas were characterized by rapid repetitive activity with a high degree of electrogram similarity. Methods Patient CharacteristicsWe enrolled 53 patients (55±8 years) with symptomatic drug-refractory nonparoxysmal AF who underwent radiofrequency ablation guided by NavX system (St Jude Medical Inc, MN). The study cohort included 31 patients (58%) with persistent AF (duration <1 year but >7 days) and 22 patients (42%) with long-lasting persistent AF (duration of ≥1 year; Table 1). All patients presented with incessant AF in the beginning of the procedure. The patients were excluded from the study if they were in sinus rhythm or had spontaneous termination of AF before the PVI. Electrophysiological StudyAn electrophysiological study and catheter ablation in the fasting state were performed in each patient after informed consent was obtained. All antiarrhythmic drugs, except amiodarone, were discontinued for ≥5 half-lives before the start of the procedure. Overall, 19 patients (36%) were treated with amiodarone before the procedure because of symptomatic AF, but no patients received that drug during the electrophysiological procedure. Electroanatomic mapping was performed in all patients. The details of the mapping have been described in other previous studies. 10,11 Signal Acquisition and Linear AnalysisDuring AF, point-by-point mapping was ...

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RF ablation prevents the progression of paroxysmal AF effectively, except in patients with increased LA diameter and LV end-systolic diameter on echocardiogram, suggesting more aggressive rhythm control therapies should be considered in these patients.

The long-term clinical impact of premature ventricular complexes (PVCs) on mortality and morbidity has not been fully studied. This study aimed to investigate the association between the burden of PVCs and adverse clinical outcome.A total of 5778 subjects, who were pacemaker-free and ventricular tachycardia-free at baseline, received 24-hour electrocardiography monitoring between January 1, 2002 and December 31, 2004. Clinical event data were retrieved from the Bureau of National Health Insurance of Taiwan. Multivariate Cox hazards regression models and propensity-score matching were applied to assess the association between PVCs and adverse clinical outcome.Average follow-up time was 10�± 1 year. In all, 1403 subjects expired, 1301 subjects were hospitalized in the cardiovascular (CV) ward, 3384 were hospitalized for any reason, and 631 subjects developed new-onset heart failure (HF). The optimal cut-off PVC frequency (12 beats per day) was obtained through receiver operator characteristic curves, with a sensitivity of 58.4% and specificity of 59.8%. Upon multivariate analysis, a PVC frequency >12 beats per day was an independent predictor for all mortality (hazard ratio [HR]: 1.429, 95% confidence interval [CI]: 1.284–1.590), CV hospitalization (HR: 1.127, 95% CI: 1.008–1.260), all-cause hospitalization (HR 1.094, 95% CI: 1.021–1.173), and new-onset HF (HR: 1.411, 95% CI: 1.203–1.655). Subjects with a PVC frequency >12 beats per day had an increased risk of cardiac death attributable to HF and sudden cardiac death. The incidence rates for mortality and HF were significantly increased in cases of raised PVC frequency. Propensity-score matching analysis also echoed the main findings.Increased PVC burden was associated with a higher incidence of all-cause mortality, CV hospitalization, all-cause hospitalization, and new-onset HF which was independent of other clinical risk factors.