Key result
Lower dominant frequency and regularity index correlated with early self-termination of PVT/VF, with regularity remaining an independent predictor of self-termination (HR 0.954; 95% CI 0.928-0.980).
Why the study?
The spectral dynamics of early spontaneous polymorphic ventricular tachycardia and ventricular fibrillation in humans had not been determined.
Do spectral dynamics (dominant frequency and regularity index) of ICD signals predict spontaneous termination of polymorphic ventricular tachycardia and fibrillation?
Observational (n=87)
Do spectral dynamics (dominant frequency and regularity index) of ICD signals predict spontaneous termination of polymorphic ventricular tachycardia and fibrillation?
Hazard Ratio: 0.954 (95% CI 0.928–0.98)
Lower frequency and regularity of PVT/VF signals correlate with early self-termination, which could inform the development of new ICD algorithms to reduce inappropriate shocks.
May inform ICD algorithm development to reduce shocks; hypothesis-generating, requiring prospective validation before clinical use.
AIMS: To determine the spectral dynamics of early spontaneous polymorphic ventricular tachycardia and ventricular fibrillation (PVT/VF) in humans. METHODS AND RESULTS: Fifty-eight self-terminated and 173 shock-terminated episodes of spontaneously initiated PVT/VF recorded by Medtronic implanted cardiac defibrillators (ICDs) in 87 patients with various cardiac pathologies were analyzed by short fast Fourier transform of shifting segments to determine the dynamics of dominant frequency (DF) and regularity index (RI). The progression in the intensity of DF and RI accumulations further quantified the time course of spectral characteristics of the episodes. Episodes of self-terminated PVT/VF lasted 8.6 s [95% confidence interval (CI): 8.1-9.1] and shock-terminated lasted 13.9 s (13.6-14.3) (P < 0.001). Recordings from patients with primarily electrical pathologies displayed higher DF and RI values than those from patients with primarily structural pathologies (P < 0.05) independently of ventricular function or antiarrhythmic drug therapy. Regardless of the underlying pathology, the average DF and RI intensities were lower in self-terminated than shock-terminated episodes [DF: 3.67 (4.04-4.58) vs. 4.32 (3.46-3.93) Hz, P < 0.001; RI: 0.53 (0.48-0.56) vs. 0.63 (0.60-0.65), P < 0.001]. In a multivariate analysis controlled by the type of pathology and clinical variables, regularity remained an independent predictor of self-termination [hazard ratio: 0.954 (0.928-0.980)]. Receiver operating characteristic (ROC) curve analysis of DF and RI intensities demonstrated increased predictability for self-termination in time with 95% CI above the 0.5 cut-off limit at about t = 8.6 s and t = 6.95 s, respectively. CONCLUSION: Consistent with the notion that fast organized sources maintain PVT/VF in humans, reduction of frequency and regularity correlates with early self-termination. Our findings might help generate ICD methods aiming to reduce inappropriate shock deliveries.
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Calvo et al. (2022) conducted an observational in Polymorphic ventricular tachycardia and ventricular fibrillation (n=87). Regularity index (RI) was evaluated on Self-termination of PVT/VF (HR 0.954, 95% CI 0.928-0.980). Lower dominant frequency and regularity index correlated with early self-termination of PVT/VF, with regularity remaining an independent predictor of self-termination (HR 0.954; 95% CI 0.928-0.980).
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