Electrolyte changes in heart tissue and coronary arterial and venous plasma following coronary occlusion. Circ Res

BIOCHEMICAL reactions of myocardialcells to infarction are of basic interest in arrhythmia research. The purpose of the present investigation was to measure in the same dogs concentrations of K, Na, Ca and Mg in coronary sinus and arterial blood before infarction, during a period of ventricular arrhythmia following coronary artery occlu-sion, and in infarcted and noninfarcted heart tissue. For comparative purposes, similar analyses were made in control, sham-operated animals. Methods Myocardial infarction was produced by the method of Harris1 which consisted of ligating the left anterior descending coronary artery in 2 stages. The resultant ventricular arrhythmia, •which begins 5 to 6 hours following occlusion with the appearance of scattered ectopic beats and then develops into a nearly complete ventricular tachy-cardia 10 to 15 hours postligation, has been de-scribed by Clark and Cummings.2 For controls, similar experiments were carried out on sham-operated animals in which ligatures were merely placed under the coronary artery. Blood samples for hematocrit and plasma elec-trolyte determinations were obtained by direct puncture of the coronary sinus and the common carotid artery. At the start of the coronary occlu-sion and sham-ligation experiments, 2 control plasma samples were collected 30 minutes apart. Then, beginning 8 hours after ligature placement, additional plasma samples were obtained at hourly intervals. An 8 to 11 hour postligation collectio