Key Points
- To investigate the effects of chronic exercise on myocardial infarct size and vascularity in rats after coronary artery occlusion.
- Rats were forced to swim 1 hr/day, 5 days/week for 5 weeks.
- Myocardial capillary bed was perfused with carbon black, and histologic sections were examined for capillary/fiber ratios and fiber diameter.
- After exercise, some rats underwent left coronary artery occlusion, and myocardial infarct size was measured.
- Infarct size in E rats was 21.5 +/- 1.9% of the left ventricle compared to 31.3 +/- 2.6% in C rats (P < 0.005), representing a 30% reduction.
- Capillary/fiber ratio increased by 30% in E rats (0.87 +/- 0.06) compared to C rats (0.67 +/- 0.04, P < 0.05).
- No differences in ventricular weight or myocardial fiber diameter were observed between the groups.
Structured PICO
Does chronic exercise reduce myocardial infarct size after coronary artery occlusion in rats?
PPopulationRats (n=60 total; 8 for histologic capillary assessment, 52 for infarct size assessment)
IInterventionChronic exercise (forced swimming 1 hour/day, 5 days/week for 5 weeks)
CComparatorSedentary controls
OOutcomeMyocardial infarct size measured by planimetry of histologic sections of serial slices of left ventricle 48 hours after left coronary artery occlusionsurrogate
Chronic exercise reduces myocardial infarct size following coronary artery occlusion in a rat model, potentially due to increased myocardial vascularity.