| Abstract: | ![]()
Central hemodynamics at rest and during supine ergometer exercise have been studied in 12 hypertensive subjects and three healthy persons before and 20 min after 5 mg of intravenous propranolol. Cardiac output (CO) decreased by 19% at rest (p less than 0.001) and by 15% during exercise (p less than 0.001). Pulmonary capillary wedge pressure (PCP) during exercise rose after beta-blockade by 56% to 28 mm Hg (p less than 0.001); a similar increase could be observed in pulmonary artery pressure (PAP) and right atrial mean pressure (RAM). Brachial artery mean pressure at rest did not change significantly; during exercise this value was 6% below the pretreatment level (p less than 0.001). In order to evaluate the influence of digitalis on beta-blocker induced hemodynamic changes, measurements were repeated 30 min after administration of 0.6 mg beta-Methyldigoxin intravenously. After addition of digitalis, average PCP during exercise was significantly lower than after beta-blockade alone (22.8 mm Hg, p less than 0.001). Likewise, PAP and RAM after digitalis were lower than after propranolol alone. CO did not change following digitalis administration. These findings indicate that digitalis partially counteracts the elevation of filling pressures induced by beta-blocking agents but leaves CO unchanged. |
