Abstract
The effects of sodium antimony and potassium antimony on contractility, coronary blood flow, and electrocardiogram were studied in isolated perfused dog hearts as well as in intact open-chested dogs.
The isolated heart preparation used was a spontaneously beating dog heart perfused with blood from a donor animal. Myocardial contractility was measured by strain gauge arches sutured to the myocardial surface. Coronary vasomotor effects were investigated by observing changes in the amplitude of the perfusion pressure at constant flow.
Antimony in doses of 10 to 15 mg/kg of body weight injected as a single dose into the coronary circulation of the isolated heart produced a progressive decrease in myocardial contractile force which was not reversible. The same dose injected intravenously was fatal in intact open-chested dogs. Antimony decreased the perfusion pressure at constant flow in the isolated heart, which indicates decreased coronary vasomotor tone. In the normally perfused heart this decreased vasomotor tone would tend to improve coronary circulation; however, the increases in coronary circulation were not adequate to counteract the decreased contractile force produced.
In the intact animals the myocardial contractile force also decreased progressively, with the animals dying from myocardial insufficiency and finally ventricular fibrillation.