Improved Cardiac Performance during Exercise Following Hydralazine Treatment in Chronic Heart Failure

Abstract Nine male patients with stable chronic heart failure of different etiology and optimally treated with digoxine and diuretics were given hydralazine. 50 mg b.i.d., during three months. Hemodynamic parameters were evaluated during upright submaximal exercise. An increase in cardiac index due to an increased stroke volume was noted following the first dose of hydralazine. After three months' treatment, cardiac index was further increased. The arteriovenous oxygen difference was initially unchanged, but significantly decreased following long-term treatment. These findings may indicate different effects of hydralazine acutely and after long-term treatment. It is suggested that the initial increase in blood flow is directed mainly to regions other than the exercising muscles, while more blood is directed to the muscles after long-term treatment. A possible mechanism to explain this postulated difference is discussed.