Heart rate variability significantly declined before the onset of ventricular tachyarrhythmias compared with control conditions, suggesting sympathoexcitation independent of antiarrhythmic drugs.
Observational (n=58)
BACKGROUND: The recent availability of implantable cardioverter-defibrillators (ICDs) that record 1024 R-R intervals preceding a ventricular tachyarrhythmia (VTA) provides a unique opportunity to analyze heart rate variability (HRV) before the onset of VTA. METHODS AND RESULTS: Fifty-eight post-myocardial infarction patients with an implanted ICD for recurrent VTA provided 2 sets of 98 heart rate recordings in sinus rhythm: (1) before a VTA and (2) during control conditions. Three subgroups were considered according to the antiarrhythmic (AA) drug regimen. A state of sympathoexcitation was suggested by the significant reduction in HRV before VTA onset compared with control conditions. beta-Blockers and dl-sotalol enhanced HRV in control recordings; nevertheless, HRV declined before VTA independent of AA drugs. A gradual increase in heart rate and decrease in sinus arrhythmia at VTA onset were specific findings of patients who received dl-sotalol. CONCLUSIONS: The peculiar heart rate dynamics observed before VTA onset are suggestive of a state of sympathoexcitation that is independent of AA drugs.
Pruvot et al. (Tue,) conducted a observational in Post-myocardial infarction with recurrent ventricular tachyarrhythmia (n=58). Period preceding ventricular tachyarrhythmia (VTA) vs. Control conditions was evaluated on Heart rate variability (HRV). Heart rate variability significantly declined before the onset of ventricular tachyarrhythmias compared with control conditions, suggesting sympathoexcitation independent of antiarrhythmic drugs.