Comparison of infarct size produced by coronary artery occlusion in purebred beagle and mixed-breed dogs.

Abstract

This investigation demonstrated a significant difference in infarct size following coronary artery occlusion between purebred beagles and mixed-breed dogs. Myocardial infarctions were produced by a two-stage ligation of the left anterior descending artery (LAD). Myocardial infarct size, expressed as percent of left ventricular mass, was determined at 24 h by nitro blue tetrazolium staining. Infarct size was significantly smaller (12.5 +/- 3.4%) and more variable (coefficient of variation 72%) in beagles than in mixed-breed animals (28.0 +/- 2.4% infarct size, 23% coefficient of variation) (p less than 0.001). Ectopic activity at 24 h was similar for both beagles and mixed breed, 92 +/- 7 and 92 +/- 2% of total heart rate, respectively. Thus this study indicates that the breed of dog (i.e., purebred beagles versus mixed-breed animals) can be an important variable in the study of infarct size resulting from coronary artery occlusion.