Hemodynamic effects of intermittent transdermal nitroglycerin in chronic congestive heart failure

The hemodynamic effects of intermittent and continuous treatment with transdermal nitroglycerin, 10 mg/24 hours, were compared in 10 patients with chronic congestive heart failure (CHF). Eight patients responded to initial application with more than a 20% reduction in mean pulmonary artery wedge pressure. Cardiac index increased from a control value of 2.1 +/- 0.5 to 2.4 +/- 0.6 liters/min/m2 at 2 hours (p less than 0.05) and mean pulmonary wedge pressure was reduced from 22 +/- 5 to 16 +/- 6 mm Hg (p less than 0.01). The 2 nonresponders had the largest left ventricular volumes on 2-dimensional echocardiograms. Responders were randomized to intermittent (16 hours/day) or continuous (24 hours/day) treatment for 1 month followed by a month of the alternate treatment. After 1 month of intermittent treatment, the hemodynamic response after reapplication was similar to the initial response. After another month of continuous treatment, hemodynamic values 24 hours after application were similar to initial control values and there was no change after removal and reapplication. Thus, the moderate vasodilator effect of transdermal nitroglycerin in CHF is maintained with intermittent treatment, whereas tolerance develops with continuous treatment.