The Effect of Captopril on Postural Hemodynamics and Autonomic Responses in Chronic Heart Failure

Both postural abnormalities and autonomic dysfunction have been identified in patients with chronic congestive heart failure (CHF). However, the effect of long-term vasodilator therapy on these phenomena has not been assessed. In this study the hemodynamic and plasma norepinephrine (PNE) responses to upright posture, as well as the cold pressor test and Valsalva's maneuver in 12 patients with severe chronic CHF during both acute and long-term captopril (CPT) therapy, were evaluated. This revealed an absence of the normal hemodynamic adjustments to upright posture and a blunted response of PNE. The heart rate and blood pressure responses to the cold pressor test and Valsalva's maneuver were similarly blunted. The reflex adjustments of systemic resistance during tilt improved with CPT therapy, but the absence of reflex tachycardia in the upright posture persisted. Additionally, there was improvement of the PNE response, and the responses of heart rate and blood pressure to the cold pressor test were virtually normalized during long-term CPT therapy. The abnormal response to the Valsalva maneuver persisted. In conclusion, hemodynamic and reflex-mediated responses to upright posture and the standard assessment of autonomic control mechanisms revealed abnormal patterns in heart failure. While the hemodynamic adjustment to postural changes and sympathetic responsiveness were improved with CPT, complete correction of these abnormalities did not occur. Whether the improvement was a nonspecific vasodilator effect or the result of specific CPT therapy remains to be determined.