The effect of cardiac irradiation upon the electrocardiogram of the normal canine heart.

Abstract

Electrocardiograms were obtained on 52 normal dogs before and after cardiac irradiation with 1,300, 2,000, and 2,500 r. No ectopic cardiac arrhythmias were noted on electrocardiograms obtained 7 to 90 days following the completion of the course of irradiation. A mean increase in the ventricular rate was noted 7 days following the completion of the course of irradiation, but was not present 30 to 60 days later. There was no prolongation of PR interval or QRS duration following cardiac irradiation. At the dosage levels employed, irradiation of the normal canine heart produced no electrocardiographic changes indicative of gross myocardial damage. This was noted to be true as long as 90 days following the completion of the course of irradiation. (auth)