Electrophysiological and haemodynamic effects of a new inotropic agent (UK14275) in the dog

1. Electrophysiological and haemodynamic effects after intravenous administration of a new inotropic agent (UK14275) have been examined in open-chest dogs under pentobarbitone anaesthesia. 2. UK14275 produced slight shortening of QT interval, ventricular functional refractory period and atrio-ventricular conduction time but did not affect action potential duration or endocardial-epicardial conduction time. 3. Cardiac output and left ventricular dP/dt increased, and systemic vascular resistance fell. 4. An end-systolic pressure gradient developed between left ventricle and aorta attributable to left ventricular cavity obliteration.