Hemodynamic response to digitalization in patients with hypertensive cardiovascular disease

Abstract

Twenty-eight patients with hypertensive cardiovascular disease (HCD) and incipient myocardial dysfunction underwent hemodynamic studies at rest and during exercise before and 30 minutes after administration of 0.6 mg beta-methyl-digoxin intravenously. Measurements were made during right heart catheterization with a balloon-tipped catheter. The hemodynamic changes after administration of digitalis did not demonstrate a consistent and uniform improvement of cardiac performance in all patients with HCD and myocardial dysfunction. When separating 11 patients with pervious myocardial infarctions or documented coronary artery disease (CAD) (= Group I) from the remaining 17 subjects without clinical and/or angiographic signs of CAD (= Group II), there were significant differences in the hemodynamic response to digitalis: In Group I, pulmonary artery wedge pressure (PAWP) after digitalis decreased only slightly and insignificantly from 8.7 to 7.4 mm Hg at rest and from 27.6 to 26.4 mm Hg during steady state exercise. Cardiac output (CO) remained essentially unchanged with a tendency to decrease after digitalis: 5.9 vs. 5.8 L/min at rest and 11.5 vs 11.1 L/min during exercise. At rest, even patients of Group II showed only minor decrease of PAWP from 8.8 to 7.2 mm Hg; during exercise these patients demonstrated marked improvement of cardiac performance with a significant decrease of PAWP after digitalis from 27.8 to 22.3 mm Hg (p less than 0.01). With one exception, there was a more or less pronounced reduction of PAWP after the drug was given. No significant change of CO after digitalis was measured in this group: 6.2 vs. 5.9 L/min at rest and 13.4 vs. 13.5 L/min during exercise. The different hemodynamic patterns of responders and non-responders to the glycoside will be discussed.