Altered blood pressure variability in patients with congestive heart failure

Objective Congestive heart failure (CHF) is characterized by sympathetic ov eractivity but reduced variability of heart interval and sympathetic nerve activity; little information exists, however, about the alterations in bloo d pressure variability in this syndrome, especially during excitatory manoe uvres such as tilting or exercise. Design and methods Nine patients with CHF (age 62 a 1 years, NYHA class II- III, ejection fraction 33 +/- 1%, peak VO2 14.1 +/- 3.2 ml/min per kg body weight [mean +/- SEM]) and eight healthy control subjects (age 58 +/- 1 yea rs) with normal left ventricular function were studied. Blood pressure (Fin apres), R-R interval (ECG) and respiration (nasal thermistor) were recorded during 15-min periods of supine rest, 70 degrees head-up tilting, submaxim al bicycling exercise and post-exercise recovery, Total variance and the po wer of the spectral components of blood pressure (HF, respiratory-related; LF, 0.03 - 0.14 Hz; and VLF, 0.02-0.003 Hz) were measured. Results Compared with control subjects, CHF patients have, first, a normal overall blood pressure variability during supine rest but a failure to incr ease this variability in response to head-up tilt and exercise; second, a s uppressed LF spectral component of blood pressure at rest and in response t o head-up tilt and exercise; and third, reappearance of LF blood pressure p ower during postexercise recovery. Conclusions In CHF patients, overall blood pressure variability and its LF spectral component are altered at rest and during sympathoexcitatory manoeu vres. Somewhat paradoxically, however, the depressed LF blood pressure powe r is partially restored during a 15-min recovery period, indicating that at least part of the CHF-related alterations of blood pressure variability ha ve the potential to revert back towards normal under appropriate physiologi cal circumstances. (C) Lippincott Williams & Wilkins.