Exercise and diastolic function after myocardial infarction.
OBJECTIVE
The purpose of this study was to determine the effects of exercise training on LV geometry and LV diastolic function in a rat model of MI.


METHODS
One month after MI induced by ligation of the left anterior descending artery (N = 45) or sham operation (N = 26), rats were randomized to either a sedentary or exercise group. Exercise consisted of treadmill running at 24 m.min-1, 1 h.d-1, 5 d.wk-1, for 3 wk. Passive LV pressure volume relationships were established with an isolated, red-cell-perfused Langendorff preparation. Infarct size was determined histologically and categorized as small (<30% of LV) or large (> or =30% of LV).


RESULTS
LV end-diastolic pressure-volume relationships were shifted rightward with increasing infarct size (P < 0.05). Exercise training further shifted the LV end-diastolic pressure-volume relationships rightward in sham, small MI and large MI (P < 0.05). Peak LV developed pressure was comparable in sedentary and exercised-trained hearts in sham, small MI, and large MI. LV diameter and septal wall thickness were greatest in large MI (P < 0.05). Exercise-trained hearts showed a tendency for a greater LV diameter and septal wall thickness in sham, small MI, and large MI. Scar thinning was most notable in large MI (P < 0.05).


CONCLUSIONS
Moderate-intensity treadmill running induces myocardial remodeling and a rightward shift in the LV end-diastolic pressure-volume relationship after MI, an adaptation similar to what is observed with exercise training in sham hearts without MI.
Libonati
Joseph R
JR
Department of Kinesiology, Temple University, Philadelphia, PA 19003, USA. jlibonat@astro.temple.edu
D000818:Animals; D003971:Diastole; D004195:Disease Models, Animal; D005081:Exercise Therapy; D006801:Humans; D008297:Male; D009203:Myocardial Infarction / Q000534:rehabilitation* / Q000662:veterinary; D051381:Rats; D017208:Rats, Wistar; D012420:Running; D016896:Treatment Outcome; D016277:Ventricular Function, Left; D020257:Ventricular Remodeling