Autonomic nervous system activity and the spontaneous initiation of ventricular tachycardia

[摘要] Objectives. We hypothesized that neurohormonal activity contributes to the initiation of sustained ventricular tachycardia (VT) as reflected in indices of heart rate variability (HRV). Background. Autonomic nervous system activity participates in experimental arrhythmias but clinical studies have been inconsistent. Methods. Holter electrocardiograms from 53 patients with VT were analyzed. Heart rate variability indices were determined over 5 and 15 min and 24 h and examined for changes before the onset of VT. Heart rate variability indices in the frequency domain included ultra low frequency power (PP) (ULFP): 0-0.0033 Hz; very low FP (VLFP): 0.0033-0.01 Hz; low PP (LFP): 0.04-0.15 Hz; high FP (HFP): 0.15-0.4 Hz; total power (TP); normalized LFP (LFPn); normalized HFP (HFPn), and the ratio: LFP/HFP. Results. Heart rate variability indices were severely diminished: TP: 12,009 +/- 11,076 ms(2); ULFP: 10,087 +/- 9,565 ms(2); VLFP: 1,416 +/- 1,571 ms(2); LFP: 544 +/- 620 ms(2); HFP: 161 +/- 176 ms(2), and dLFP/HFP: 3.68 +/- 2.83. Heart rate increased before VT (80.4 +/- 17.3 to 85.3 +/- 17.4 bpm, p < 0.001). Several HRV variables declined 30 min before VT compared to 24-h values (VLFP: -5.89 +/- 17.81%, p = 0.031; LFP: -5.23 +/- 14.3%, p = 0.003; HFP: -435 +/- 13.7%, p = 0.04). LFPn and the LFP/HFP ratio decreased significantly before the onset of VT (-17.7 +/- 46.9%, p = 0.035 and -8.24 +/- 38.8%, p = 0.037, respectively), whereas HFPn increased slightly (1.29 +/- 29.9%, p = 0.097). Conclusions. Heart rate rose, whereas LFP, LFPn and LFP/ HFP fell before the onset of VT. This pattern of changes could be explained by a rise in sympathetic activity and saturation of the HRV signal resulting in dissociation of the average and rhythmical effects of sympathetic activity. These findings suggest that alterations in autonomic activity contributed to arrhythmogenesis in this group of patients. (J Am Coll Cardiol 1998;32:1891-9) (C) 1998 by the American College of Cardiology.

[发布日期] 1998-12-01

[效力级别]  Proceedings Paper