Favorable effects of hydralazine on the hemodynamic response to isometric exercise in chronic severe aortic regurgitation

Abstract The hemodynamic effects of isometric exercise and the response to hydralazine therapy were evaluated in 11 patients with chronic, severe aortic regurgitation (AR). Isometric exercise produced a significant increase in heart rate (from 78 ± 11 to 93 ± 19 beats/min [mean ± standard deviation], p p 2 ), systemic vascular resistance (from 1,097 ± 257 to 1,171 ± 284 dynes s cm −5 ), pulmonary vascular resistance (from 120 ± 76 to 130 ± 89 dynes s cm −5 ) and stroke volume index (from 44 ± 10 to 43 ± 12 ml/m 2 ). After oral hydralazine administration (100 to 300 mg), hemodynamic values during isometric exercise were: Heart rate increased further, to 105 ± 14 beats/min ( p 2 (p 2 (p −5 (p −5 (NS). Thus, isometric exercise in patients with chronic severe AR is associated with only a slight and insignificant increase in systemic vascular resistance, but a marked increase in pulmonary artery wedge pressure. Direct arteriolar vasodilation with hydralazine results in a significant attenuation of pulmonary artery wedge pressure increase during isometric exercise and leads concomitantly to a significant augmentation of stroke volume and cardiac output. These findings substantiate the value of hydralazine therapy in patients with chronic, severe AR.