Autonomic modulation and clinical outcome in patients with chronic heart failure.

Abstract Objective Several studies documented the relevance of autonomic activity in the pathophysiology of heart failure. In our study we evaluated the adjustment of this activity under different stimuli, by means of heart rate variability (HRV), and correlated these findings with long-term mortality and sustained VT occurrence. Patients and method Fifty-three patients (mean age 54±9 years) with heart failure were submitted to time and frequency domain HRV analysis. This latter analysis was performed at rest, during paced breathing and during passive tilt. Results Lower standard deviation of RR intervals (76.76±24 versus 107.70±43, p =0.02), mean of the 5-min standard deviations of RR intervals (35.14±15 versus 62.39, p p =0.02), and baseline Low-Frequency (LF) power (15.15±12 versus 40.39±24 nu, p =0.001) characterized patients who died. Paced breathing induced a significant reduction of LF (40.39±24 to 20.12±18 nu, p p p Conclusions Patients with heart failure with a better prognosis are characterized by a responsiveness of autonomic modulation. Simple maneuvers, such as tilting and paced breathing, seem to provide more useful information, than the baseline evaluation of autonomic status, in identifying patients with a higher mortality. Time domain analysis was more helpful to estimate arrhythmic risk.