Immediate effects of hydralazine-isosorbide dinitrate combination on exercise capacity and exercise hemodynamics in patients with left ventricular failure.

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Abstract
Resting hemodynamics improve during vasodilator administration in patients with congestive heart failure (CHF), but the effects of these agents during exercise is unknown. Patients (22) with class II or III CHF performed bicycle exercise to symptomatic maximum before and 90 min after random double-blind administration of oral hydralazine (100 mg) and isosorbide dinitrate (40 mg) (11 patients, group 1) or placebo (11 patients, group 2). Exercise duration was unchanged after treatment in both groups. Maximal O2 consumption changed insignificantly in both groups, from 12.6 .+-. 1.2 (SEM [standard error of the mean]) to 13.6 .+-. 1.6 ml/kg per min in group 1, and from 11.7 .+-. 1.4 to 13.4 .+-. 1.7 ml/kg per min in group 2. Maximal cardiac index was unchanged in both group 1 (4.00 .+-. 0.33 to 4.41 .+-. 0.29 l/min per m2) and group 2 (4.11 .+-. 0.43 to 4.14 .+-. 0.42 l/min per m2). Systemic vascular resistance at peak exercise was also unchanged in both group 1 (14.1 .+-. 1.6 to 11.8 .+-. 1.0 units) and group 2 (14.7 .+-. 1.6 to 13.5 .+-. 1.6 units). At submaximal exercise (300 kilopound-meters/min), cardiac index after treatment increased in group 1 (0.51 .+-. 0.18 l/min per m2, P < 0.05) and systemic vascular resistance decreased (-3.3 .+-. 1.3 units, P < 0.05), but were unchanged in group 2. Although vasodilators do not improve maximal exercise capacity acutely, they can improve hemodynamics at lower work loads which may be better tolerated in patients with CHF.