Decreased baroreflex sensitivity assessed from phase IV of Valsalva maneuver in mild congestive heart failure

Decreased sensitivity of cardiopulmonary and arterial baroreceptors has bee n hypothesized to sustain sympathetic activation in patients with heart fai lure. In the present investigation the relationship between the impairment of baroreflex sensitivity and clinical severity of congestive heart failure was investigated. The authors studied 58 patients with heart failure (14 i n NYHA class I, 22 in NYHA class II, and 22 in NYHA class III), 38 women an d 20 men, age range 28-65 years. Thirty-two patients suffered from idiopath ic dilated cardiomyopathy and 26 from coronary heart disease. As control gr oup they examined 21 age-matched subjects. Baroreceptor sensitivity was stu died by using the Valsalva maneuver as stimulus. Arterial pressure and hear t rate were measured noninvasively by Finapres instrument (Ohmeda) and sign als were recorded and elaborated with a personal computer. A decrease of ba roreflex sensitivity was already demonstrable in NYHA class I patients (4.7 2 +/- 3.31 vs 9.25 +/- 5.05 msec/mm Hg in control group) (p < 0.005). 14 fu rther impairment of baroreceptor response was found in patients in NYHA cla ss II (1.94 +/- 2.88 msec/mm Hg, p < 0.001) and class III (1.78 +/- 1.52 ms ec/mm Hg, p < 0.001). Baroreceptor response showed a significant correlatio n with functional NYHA class (r = 0.61, p < 0.001) and anaerobic threshold (r = 0.57, p < 0.001) while the correlation was less tight with left ventri cular end-diastolic diameter, fractional shortening, left ventricular eject ion fraction, pulmonary mean arterial blood pressure, cardiac index, distan ce at 6 minutes walk corridor test, and maximal oxygen consumption ((V) ove r dot o(2)max). These results suggest that baroreceptor function may be imp aired early in the clinical course of heart failure and may contribute to s ympathetic activation.