[Effects of a new beta-blocker (CI 775) on left ventricular hemodynamics at rest and during exercise (author's...

The effects of a new beta-blocking agent (CI 778) were studied in 8 patients in whom non-invasive data suggested absence of significant organic heart disease. The left ventricular hemodynamics at rest and during bicycle exercise were measured before and after intravenous administration of 0,9 mg/kg body weight. With exercise there was a significantly smaller increment of heart rate (18%) after beta-blockade. Stroke volume index at rest was significantly lower (17%) after administration of CI 775; the difference disappeared with exercise. There was an 18% decrease of the resting cardiac output after CI 775 and a 23% decrease with exercise. Significant changes at rest and with exercise indicating a negative inotropic action of CI 775 were noted for max dP/dt and peak measured velocity of circumferential fiber shortening (Vpm). The left ventricular enddiastolic pressure with exercise increased with borderline significance by 41% after CI 775. Also left ventricular stroke work index at rest and with exercise decreased moderately (n.s.), the systemic arterial resistance changed to the same extent as cardiac output decreased. Also the arterial venous oxygen difference increased after CI 775 only according to the decrease of cardiac output. The data suggest the hemodynamic properties of CI 775 are located between propranolol and practolol within the spectrum of available beta-blockers.