Distinctive RR Dynamics Preceding Two Modes of Onset of Spontaneous Sustained Ventricular Tachycardia

Abstract

HR and RRV did not change before type 1 VTsm, suggesting that short-term changes in autonomic activity were not essential to initiation of apparent PVC-triggered VTsm. In contrast, RR interval dynamics before type 2 VTsm suggested that short-term changes in neurohormonal activity contributed to arrhythmia initiation. Heterogeneities in arrhythmia onset may reflect distinct triggers and substrate properties that could provide a basis for effective therapeutic targets.

Heart Rate Dynamics at the Onset of Ventricular Tachyarrhythmias as Retrieved From Implantable Cardioverter-Defibrillators in Patients With Coronary Artery Disease

“…Second, the mean LVEF of our subgroup without AA drugs (0.28) is lower than the mean LVEF (0.34 to 0.43) in previous studies. 4,6,9,11 The HR is known to be inversely correlated with LVEF, 20 which was confirmed in the present study. The low LVEF may have prevented a further increase in HR within this very short period.…”

“…It has been reported that HRV before sVT decreased for sVTs with an initial complex that had a waveform identical to subsequent complexes (type 2), whereas HRV remained unchanged for sVTs triggered by morphologically distinct early cycle (type 1). 11 Due to limited ICD memory, these data were not available in the present study. For some patients, up to 4 VTA episodes were included in the analysis.…”

“…Total HRV seems to increase before non-sVT but apparently decreases or remains unchanged before sVT. 4,6,9,11 In our study, a gradual decrease or no change in HRV indices was noticed before VTA onset. The removal of non-sVTA episodes should have enhanced the value of our findings rather than diminish it.…”

“…First, our parameters were measured in the last 4 windows of 2-minute duration before VTA, whereas others computed these indices with 5-to 30-minute windows. 4,6,9,11 In the present study, the absence of HR rise may be due to shorter windows. Second, the mean LVEF of our subgroup without AA drugs (0.28) is lower than the mean LVEF (0.34 to 0.43) in previous studies.…”

“…In some studies, an increase in HR but no evolution of spectral indices before sVT was noted, 4 whereas other researchers have reported a decrease in HRV within 1 hour preceding sVT compared with non-sVT 6 or with 24-hour values. 6,9,11 In a recent work, we observed an increase in HR but a gradual rise in VLF power and a decline in HF power before VTA onset 7 that have not been reported by others. These findings are partially validated by the present study: a gradual decrease in HF power but no change in VLF power are noted.…”