Prognostic role of heart rate variability in patients with idiopathic dilated cardiomyopathy.
BACKGROUND
The aim of this study was to investigate whether heart rate variability may predict the outcome in patients with idiopathic dilated cardiomyopathy.


METHODS
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%).


RESULTS
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).


CONCLUSIONS
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.
Lanza
G A
GA
Institute of Cardiology, Catholic University of the Sacred Heart, Rome, Italy.
Bendini
M G
MG
Intini
A
A
De Martino
G
G
Galeazzi
M
M
Guido
V
V
Sestito
A
A
D000368:Aged; D002311:Cardiomyopathy, Dilated / Q000503:physiopathology*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D016016:Proportional Hazards Models; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology