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Increased cycle length variability during ventricular fibrillation: a novel predictor of arrhythmia recurrence
Hisashi Yokoshiki1, Tetsuro Kohya, Minoru Sato
1Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan. yokoshh@med.hokudai.ac.jp
Insights
Increased cycle length variability during ventricular fibrillation (VF) predicts arrhythmia recurrence in patients with implantable cardioverter defibrillators (ICDs). These measures may indicate electrical heterogeneity and future arrhythmic events.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Devices
Background:
- Ventricular fibrillation (VF) cycle length (CL) variability is a potential indicator of electrical heterogeneity.
- Understanding VF CL variability can aid in predicting arrhythmic events and optimizing implantable cardioverter defibrillator (ICD) therapy.
Purpose of the Study:
- To evaluate the clinical significance of VF CL variability in predicting recurrent ventricular arrhythmias.
- To assess the utility of mean successive differences (MSD) and coefficient of variation (CV(FF)) of VF CL as predictors of arrhythmia recurrence.
Main Methods:
- Analysis of VF CL, MSD, and CV(FF) in 26 patients undergoing ICD implantation.
- Calculation of VF CL variability parameters during induced VF for defibrillation testing and programmed ventricular stimulation.
- Application of Bland-Altman method for assessing repeatability of VF CL variability measures.
- Kaplan-Meier estimates and multivariate analysis to determine predictive value for arrhythmia recurrence.
Main Results:
- Patients with recurrent ventricular arrhythmias exhibited significantly higher MSD and CV(FF) compared to those without recurrence.
- MSD >= 20 ms and CV(FF) >= 12 were identified as predictors of higher arrhythmia recurrence rates.
- CV(FF) >= 12 was a significant independent predictor of recurrent arrhythmic events by multivariate analysis.
Conclusions:
- Increased VF CL variability, quantified by MSD and CV(FF), is associated with a higher likelihood of arrhythmia recurrence.
- These variability measures may reflect underlying electrical heterogeneity and serve as valuable biomarkers for predicting future arrhythmic events.
- VF CL variability analysis holds potential for refining risk stratification and guiding therapeutic decisions in patients with ICDs.
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 x 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 <.005, (**)P <.001 vs. nonrecurrence group). Relatively good repeatability of mean VFCL, MSD and CV(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 >or= 20 ms and CV(FF) >or= 12 predicted higher arrhythmia recurrence (MSD, P =.039; CV(FF), P =.0069 by the log-rank test). By multivariate analysis, CV(FF) >or= 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.