Prognostic value of heart rate variability in time domain analysis in congestive heart failure

Aims: Analysis of heart rate variability is a noninvasive tool that allows to study autonomic control of the heart. Several studies have shown disturb ed heart rate variability in patients with chronic heart failure (CHF). We sought to assess the prognostic value of time domain measures of heart rate variability in CHF. Methods and Results: We prospectively enrolled 190 patients with CHF in sin us rhythm, mean age 61 +/- 12 years, 109 (57.4%) in NYHA class II and 81 (4 2.6%) in class III or IV, mean cardiothoracic ratio 57.6 +/- 6.4% and mean left ventricular ejection fraction 28.2 +/- 8.8 %, 85 (45%) with ischemic a nd 105 (55%) with idiopathic dilated cardiomyopathy. Time domain measures o f heart rate variability were obtained from 24 h Holter ECG recordings. Dur ing follow-up (22 +/- 18 months), 55 patients died. In multivariate analysi s, independent predictors for all-cause mortality were: ischemic heart dise ase, cardiothoracic ratio greater than or equal to 60% and standard deviati on of all normal RR intervals < 67 ms (RR = 2.5, 95% CI 1.5-4.2). Conclusions: Depressed heart rate variability has independent prognostic va lue in patients with CHF.