COMPARISON OF HEMODYNAMIC-RESPONSES TO CILNIDIPINE AND NICARDIPINE INAN EXPERIMENTAL-MODEL OF ACUTE CONGESTIVE-HEART-FAILURE

1, The haemodynamic effects of cilnidipine, a new calcium channel bloc ker, were examined in a canine model of acute congestive heart failure and were compared with those of nicardipine at equihypotensive doses. 2, The model was prepared by injections of saponin into coronary arte ries of anaesthetized open-chest dogs followed by volume loading and c ontinuous i,v, infusion of methoxamine, After the treatment, aortic bl ood flow (AoF) and left ventricular dP/dt markedly decreased, while le ft ventricular end-diastolic pressure (LVEDP), right atrial pressure a nd systemic vascular resistance (SVR) increased. Cilnidipine (0,3, 1.0 and 3.0 mu g/kg per min), nicardipine (0,3, 1.0 and 3.0 mu g/kg per m in) or the respective vehicle was given i,v, after accomplishment of h eart failure. 3, These drugs both produced a comparable reduction in a ortic pressure and an increase in AoF associated with profound decreas es in LVEDP, SVR and coronary vascular resistance. In contrast, admini stration of nicardipine was associated with significant increases in h eart rate and cardiac contractility but that of cilnidipine was not. 4 . These results indicate that cilnidipine as well as nicardipine can e xert beneficial haemodynamic effects in a model of acute heart failure probably through lessening afterload and cilnidipine may moderate ref lex-induced sympathetic stimulation.