Hemodynamic and neurohumoral responses to exercise in patients with congestive heart failure.

Abstract

Hemodynamic and neurohumoral responses to supine bicycle exercise were evaluated in 16 patients with congestive heart failure (New York Heart Association functional class II-III) and in 8 normal controls. We determined cardiac output by the dye-dilution method, and forearm hemodynamics by plethysmography. The patients had lower resting cardiac and stroke indexes (p < 0.05) than the normal controls. During exercise, the increase in the cardiac index due to an increase in heart rate, was less than that in the controls. Resting and exercise systemic vascular resistance indices were higher in the patients (p < 0.05). The patients had lower resting forearm blood flow and higher forearm vascular resistance (p < 0.05), and the increases during exercise were comparable in the 2 groups. However, forearm venous tone and venous pressure increased more in the patients (p < 0.05). Exercise duration was shorter in the patients (p < 0.01). Resting plasma angiotensin II and norepinephrine were similar in the 2 groups, but plasma 6-keto-prostaglandin F1 alpha and atrial natriuretic peptide were higher in the patients. During exercise, all of these neurohumoral parameters rose more in the patients than in the controls (p < 0.05). Thus, the patients exhibited impaired central and peripheral hemodynamics both at rest and during exercise. The excessive exercise responses of all of the neurohumoral factors suggest that both vasoconstrictor and vasodilator systems are activated in heart failure.