The effect of trimepranol in the ischaemic focus in the dog

The authors tested metipranolol (Trimepranol Spofa) for its effect in the ischaemic focus in the dog. Electrodes were sutured on the left ventricular myocardial surface and a ligature was prepared on the descending branch of the left coronary artery. One week after the operation the artery was ligated without chest opening, and electrograms were recorded. Twenty-four hours after the ligation the activity of creatine phosphokinase was determined and the histological changes were examined in samples of myocardial tissue underlying the individual electrodes. The findings in control dogs and in dogs treated with Trimepranol were compared. Trimepranol manifested itself by an early decrease of heart rate and decrease of ST segments elevations in the electrograms from the myocardial surface. Twenty-four hours after coronary artery ligation no Q waves developed in a half of the sites under the exploring electrodes in the peripheral zone and there was higher preservation of CK activity in the corresponding tissue specimens. Moreover in the treated dogs the occurrence of early ventricular arrhythmias was reduced. The study proved a protective effect of the beta-blocking agent Trimepranol in the peripheral zone of the ischaemic focus in canine myocardium.