Is There a Gender Difference in Infarct Size and Arrhythmias Following Experimental Coronary Occlusion and Reperfusion?

It has been suggested that there may be gender differences in the outcome of myocardial infarction and therapies. However, there is a lack of knowledge regarding the basic science of gender difference in the setting of experimental myocadial infarction. Therefore, we performed a randomized study to determine whether there is a gender-related difference in infarct size as well as arrhythmias in an experimental model of myocardial infarction. Eleven male and 10 female adult rats were studied. All rats underwent 90 minutes of left main coronary occlusion and 4 hours of reperfusion. After 4 hours of reperfusion, the area at risk (AR) was delineated by dye injection and the area of necrosis (AN) was assessed by triphenyltetrazolium chloride staining. The electrocardiogram was recorded for the incidence of ventricular tachycardia (VT) and ventricular fibrillation (VF). The area at risk was similar between the two groups. Myocardial infarct size, expressed as a percentage of the area at risk, averaged 57.3 +/- 4.9% in male and 58.2 +/- 3.5% in female rats (p = NS). The incidences of VT and VF were similar between male and female rats during 90 minutes of ischemia. Thus, gender had no effect on the extent of myocardial injury in this model of ischemia/reperfusion. To the best of our knowledge this is the first prospective randomized experimental trial that has shown no effect of gender on myocardial infarct size.