Increased cycle length variability during ventricular fibrillation: a novel predictor of arrhythmia recurrence

Abstract

Abstract To evaluate the clinical value of cycle length (CL) variability during ventricular fibrillation (VF), 26 patients who underwent implantable cardioverter defibrillator (ICD) implantation were enrolled. In VF induced for defibrillation testing, mean and SD of VFCL, mean successive differences (MSD) of VFCL, and coefficient of variations of the VFCL (CV FF ) (SD×100/mean VFCL) were calculated. During the follow-up period of 20 ± 2 months, ventricular arrhythmias recurred in 13 patients. MSD and CV FF were 31 ± 3 * ms and 15.6 ± 1.3 ** in recurrence group (n = 13), and 17 ± 2 ms and 9.0 ±1.1 in non-recurrence group (n = 13) ( * P ** P FF in each patient was confirmed by the Bland-Altman method. In VF induced by programmed ventricular stimulation before ICD implantation, MSD and CV FF in recurrence group were also increased significantly. Kaplan-Meier estimates revealed that MSD ≥ 20 ms and CV FF ≥ 12 predicted higher arrhythmia recurrence (MSD, P = .039; CV FF , P = .0069 by the log-rank test). By multivariate analysis, CV FF ≥ 12 was a significant predictor of recurrent arrhythmic events ( P = .019). In conclusion, the CL variability of VF, which was evaluated as MSD and CV FF , is increased in patients with arrhythmia recurrence. These values may reflect the degree of electrical heterogeneity, and appears to be useful indexes of the future arrhythmic events.