Electrical Activity in Exercise Trained Infarcted Rat Hearts

Myocardial infarction (MI) is a major cause of cardiac arrhythmias. The aim of the study was to determine if exercise training changes the electrical conduction into, within and emerging from an infarcted area of a rat heart. Rats were divided into three groups: sedentary sham, sedentary MI, and exercise training MI. The impact of MI and exercise training on susceptibility to ventricular tachycardias (VTs) was evaluated by in vivo intra-cardiac pacing. Rats with sustained VTs were converted before sacrifice and electrophysiological experiments and optical imaging with voltage-sensitive dye were performed on perfused hearts.