[Hemodynamic effects of a new positive inotropic agent (AR-L 115 BS) in ischemic and nonischemic myocardiopathies]

Abstract

AR-L 115 BS is an imidazo-pyridine derivative with a positive inotropic action associated with peripheral and coronary vasodilatory properties. The effects of intravenous administration (a bolus of 0,45 mg/kg/min) were studied in 19 patients in functional class III of the NYHA classification in the absence of any previous drug therapy. Twelve patients had a primary myocardiopathy and the other 7 had coronary artery disease with akinetic anterior walls. A Swan-Ganz thermodilution catheter and a Millar microtransducer were used to measure pressures (pulmonary artery, left ventricular, aorta) and cardiac output under basal conditions and then every 2 minutes during intravenous administration of AR-L 115 BS. Left ventriculography in the 30 degrees RAO plane was performed under basal conditions and at the end of the investigation to measure volumes, ejection fraction, volumic compliance and segmental wall motion by the Stanford method. A stable concentration of circulating AR-L 115 BS was obtained (1 500 ng/ml). The positive inotropic action of the drug was responsible for a significant increase of all ejectional indices (cardiac and systolic index X 24 p. 100, p less than 0.01; ejection fraction +14 p. 100, p less than 0.01), of all indices of isometric contractility (dP/dt max +25 p. 100, velocity of contractile elements +35 p. 100, V max +30 p. 100 (p less than 0.01) and of the velocity of circumferential fibre shortening (+65 p. 100, p less than 0.001). All segmental shortening was improved.(ABSTRACT TRUNCATED AT 250 WORDS)