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

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 less than 0.05), mean blood pressure (from 83 +/- 8 to 104 +/- 20 mm Hg, p less than 0.05), mean right atrial pressure (from 3 +/- 2 to 7 +/- 5 mm Hg, p less than 0.05) and mean pulmonary artery wedge pressure (from 12 +/- 7 to 18 +/- 10 mm Hg, p less than 0.05). Small and insignificant changes were seen in cardiac index (from 3.4 +/- 0.8 to 3.9 +/- 1.0 liters/min/m2), 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/m2). After oral hydralazine administration (100 to 300 mg), hemodynamic values during isometric exercise were: Heart rate increased further, to 105 +/- 14 beats/min (p less than 0.05), mean blood pressure was 102 +/- 16 mm Hg (difference not significant [NS]) cardiac index increased markedly, to 5.2 +/- 1.4 liters/min/m2 (p less than 0.05), stroke volume index increased to 49 +/- 12 ml/m2 (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)