Abstract
Since the introduction of dichloro analogue of isoprenaline (DCI) by Powell and Slatter (1), several β-receptor blocking agents have been introduced in the present day medicine. Among these, propranolol is being used in various clinical conditions like angina pectoris (2-3), myocardial infarction (4) and ventricular arrhythmias (5-6). Further, propranolol has been used as local anaesthetic in minor surgical procedures (7). However, the clinical usefulness of these agents in various cardiac conditions is limited by the fact that they, some times, induce severe and irreversible cardiac failure. The present study has been done on the heart-lung preparation of the dog with a view to assess the relative myocardial depressant activity of INPEA and propranolol and also to find out some suitable agents which may effectively antagonize the cardiac failure caused by these agents.
