Abnormal vascular responses in human chronic cardiac failure are both endothelium dependent and endothelium independent

Objective To study underlying vascular responses in chronic heart failure in patients without ACE inhibitor treatment, and to compare them with age matched controls. Design Forearm blood flow was studied using venous occlusion plethysmography in patients with chronic heart failure (n = 12) and matched controls (n = 13), after infusion of L-NMMA (a nitric oxide synthase inhibitor), glyceryl trinitrate (an endothelium independent vasodilator), and serotonin (an endothelium dependent vasodilator). Results L-NMMA produced significant vasoconstriction in normal subjects (forearm blood flow reduced by 24%), but not in patients (6%; difference between groups p