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Post‐MI Exercise, Cardiac Remodeling and Function
Author(s) -
Powers Anthony S.,
Li Ji,
Zhang Kathy Y.,
Ji Lisa L.,
Erikson John M,
Sun Yao,
Zhang John Q.
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a742-a
Subject(s) - cardiology , medicine , cardiac function curve , ventricular remodeling , function (biology) , heart failure , biology , microbiology and biotechnology
We studied the timing effect of exercise (EX) training on Post‐MI (myocardial infarction) myocardial remodeling and function in rats. Rats were surgically induced MI (~40% infarct of left ventricle) and assigned to 6 groups (n=5/group): 1. MI‐EX starting at 1wk post‐MI (MI‐EX1), 2. MI‐Sedentary (Sed) at 1wk (MI‐Sed1), 3. Sham‐Sed at 1wk (Sham1), 4. MI‐EX starting at 4wk (MI‐EX4), 5. MI‐Sed at 4wk (MI‐Sed4), and 6. Sham‐Sed at 4 wk (Sham4). The EX groups started running on a treadmill at 1or 4 wk after MI at 16m/min, 50min/d, and 5d/wk for 8 wk. Cardiac function and left ventricle (LV) dimensions were measured prior to and after 8 wk of EX. The results showed that both LV internal diameter diastole (LVIDD) and systole (LVIDS) were dilated in all of the MI rats after 8 wk (LVIDD: MI‐EX1=11.6±0.01mm, MI‐Sed1=11.7±0.04, MI‐EX4=11.1±0.01, MI‐Sed4=11.8±0.04; LVIDS: MI‐EX1=10.0±0.01mm, MI‐Sed1=10.3±0.03, MI‐EX4=9.72±0.04, MI‐Sed4=10.0±0.05). Fractional shortening (FS) was not changed in MI‐EX1 (pre vs post: 15.8±0.95% vs 14.1±0.92), decreased in MI‐Sed1 (17.2±1.95% vs 11.61±1.25, p<0.01) and in MI‐EX4 (14.1±1.45% vs 12.6±1.23, p<0.02) after 8 wk. Stroke volume (SV) was increased in MI‐EX1 (313±15.5ul vs 589±43.7, p<0.001) but unchanged in MI‐EX4 (424±25.1 vs 439±20.2ul). Ejection fraction (EF) was unchanged in MI‐EX1(40.1±0.02% vs 36.3±0.02), but decreased in MI‐EX4 (38.1±0.03% vs 32.5±0.02, p<0.005) and in MI‐Sed groups. These parameters remained unchanged in Sham groups over 8 wk of period. The data suggest that starting EX 1wk after MI may improve cardiac function but did not prevent LV dilation.