The peripheral venodilation, principal effect of NTG and nitrates may cause a significant reduction in pulmonary venous pressure and, therefore, improve the symptoms of pulmonary venous congestion. Hemodynamic effects o high doses of oral isosorbide dinitrate in patients with chronic heart failure (N - 13). (Formula: see text). The other mechanism by which nitrates can potentially improve cardiac performance in patients with heart failure due to obstructive coronary artery disease is by relieving myocardial ischemia which tends to improve global myocardial function. Nitroglycerin or nitrates improve systolic motion of the ischemic but viable myocardial segments improved segmental wall motion consequent on relief of regional myocardial ischemia is probably related to a decrease in the determinants in oxygen demand rather than an increase in regional myocardial blood flow. An increase in collateral blood flow, however, may be contributory. Effects of nitrates on coronary dynamics and myocardial metabolism. (Formula: see text). These findings suggest with nitrates cardiac performance improves with decreased metabolic cost.