The prearrhythmic period showed a significantly higher mean heart rate compared to control segments before VT (88.5 vs 72.7 beats/min, P<0.0005) and VF (85.4 vs 73.3 beats/min, P<0.05).
Observational
Absolute Event Rate: 88.5% vs 72.7%
p-value: p=<0.0005
Patients with heart disease and decreased heart rate variability (HRV) have an increased risk of all-cause mortality as well as arrhythmic death. The question of acute changes in HRV immediately preceding arrhythmic events remains unanswered. We analyzed data from patients with implantable cardioverter defibrillators who had ventricular tachycardia (VT) or ventricular fibrillation (VF) detected by the device. The device stores 1,000 consecutive RR intervals preceding the arrhythmic event detection and before device interrogation. Compared to this control segment, the mean heart rate (HR) increased prior to the arrhythmic event for both VT (88.5 vs 72.7 beats/min, P 10%. The frequency of such beats was significantly higher in the prearrhythmic data segments than in the control segments for VT (10.7 vs 6.6/50 beats, P < 0.05) although not for VF (9.8 vs 6.1/50 beats, NS). We conclude that the HR and frequency of ectopic beats are higher prior to onset of the arrhythmic events, although HRV does not change markedly. These results are consistent with sympathetic activation being the predominant autonomic change prior to VT/VF onset in this patient population.
Němec et al. (Wed,) conducted a observational in Ventricular tachycardia or ventricular fibrillation in patients with implantable cardioverter defibrillators. Prearrhythmic period vs. Control period was evaluated on Mean heart rate prior to ventricular tachycardia (p=<0.0005). The prearrhythmic period showed a significantly higher mean heart rate compared to control segments before VT (88.5 vs 72.7 beats/min, P<0.0005) and VF (85.4 vs 73.3 beats/min, P<0.05).