Hemodynamic and myocardial energetic changes induced by the new cardiotonic agent, AR-L 115, in patients with coronary artery disease.

AR-L 115 has been shown to improve left ventricular (LV) pump function in patients with advanced congestive cardiomyopathy by the intravenous and oral routes. Since AR-L 115 effects on myocardial oxygen consumption (MVO2) and coronary blood flow (CSF) are unknown, the hemodynamic, myocardial metabolic, and ECG responses to AR-L 115 (2 mg/kg bolus) were monitored at 9-, 14-, and 9-minute intervals in seven patients with coronary disease, exhibiting ischemia during pacing stress only. Maximal responses occurred at the fourteenth minute after AR-L 115. There were (average) increases in cardiac index by 30%, heart rate by 19%, CSF by 39%, MVO2 by 34%, and LV dp/dt max by 27%. There were (average) decreases in peak LV systolic pressure by 13%, LV end-diastolic pressure by 42%, systemic vascular resistance by 34%, and in coronary vascular resistance by 37%. All changes were significant (p less than 0.05). Myocardial lactate extraction, stroke work index, and stroke index remained unchanged (p greater than 0.05). The modest increase in MVO2 is possibly explained by the increase in contractility being partially offset by reductions in LV preload and afterload. AR-L 115-improved LV pump function was accompanied by moderate increases in MVO2 and CSF but without evidence of myocardial ischemia.