Prognostic role of heart rate variability in patients with idiopathic dilated cardiomyopathy
Lanza, G.A.; Bendini, M.G.; Intini, A.; De Martino, G.; Galeazzi, M.; Guido, V.; Sestito, A.
Italian Heart Journal Official Journal of the Italian Federation of Cardiology 1(1): 56-63
2000
ISSN/ISBN: 1129-471X PMID: 10868925 Document Number: 518446
The aim of this study was to investigate whether heart rate variability may predict the outcome in patients with idiopathic dilated cardiomyopathy. Time-domain and frequency-domain heart rate variability was analyzed on 24-hour Holter recordings of 56 patients with idiopathic dilated cardiomyopathy (70% males, mean age 49 +/- 16 years; left ventricular ejection fraction 28 +/- 6%). There were 8 cardiac deaths (14.3%) and 11 arrhythmic events (19.6%, either sudden death or sustained ventricular tachycardia) at a follow-up of 18.5 months (range 3-50 months). Furthermore, 6 patients were included in the list for cardiac transplantation, leading to a prevalence of total cardiac events of 37.5 % (21 patients). All time-domain and most frequency-domain heart rate variability parameters did not show any significant relationship with the end points. However, a low frequency to high frequency (LF/HF) ratio < 1.2 was associated with cardiac death (relative risk-RR 6.8, p < 0.03), arrhythmic events (RR 11.0, p < 0.004), and total cardiac events (RR 4.8, p < 0.002). On the multivariate Cox analysis, no variable showed an independent association with cardiac death, but an LF/HF ratio < 1.2 was the only variable independently predictive of arrhythmic events (RR 8.2, p < 0.02), and the most powerful predictor of total cardiac events (RR 3.8, p < 0.009). Our data show that, in patients with idiopathic dilated cardiomyopathy, a low LF/HF ratio, as assessed on 24-hour Holter recordings, is a powerful predictor of cardiac events.