OBJECTIVE: The effects of exercise, a therapeutic tool in ischemic heart disease (IHD), may differ in ischemic and infarcted hearts. METHODS AND RESULTS: To assess this, we created coronary stenosis (CS), which reduced coronary flow reserve (CFR), or coronary occlusion to induce myocardial infarction (MI) in rats, and subjected them to treadmill exercise for either 5 (5-min Ex) or 15 min/day (15-min Ex) for 12 weeks. Left ventricular (LV) diameters were increased and ejection fractions decreased by echocardiography, and myocardial nitric oxide (NO) activity, measured by the in vitro MVO2 method, was reduced in both CS and MI rats compared with the sham. In CS rats, myocardial wall thickening fractions were not affected at 5 min of exercise, whereas they were reduced at 15 min of exercise, suggesting exercise-induced ischemia. Despite no changes in CS severity, the 5-min Ex increased CFR, ameliorated myocardial NO activity, attenuated left ventricular (LV) dysfunction and remodeling, reduced serum brain natriuretic peptide (BNP) levels, and improved survival, whereas the 15-min Ex aggravated LV dysfunction and remodeling. In contrast, neither of the exercise protocols improved these parameters in MI rats. CONCLUSIONS: Therapeutic responses to exercise differed in ischemic and infarcted hearts, partly via circulatory modulation downstream of the epicardial CS in relation to exercise-induced ischemia. When employing exercise for IHD, the causes of IHD, as well as the exercise protocols, need to be considered to achieve optimal effects.
OBJECTIVE: The effects of exercise, a therapeutic tool in ischemic heart disease (IHD), may differ in ischemic and infarcted hearts. METHODS AND RESULTS: To assess this, we created coronary stenosis (CS), which reduced coronary flow reserve (CFR), or coronary occlusion to induce myocardial infarction (MI) in rats, and subjected them to treadmill exercise for either 5 (5-min Ex) or 15 min/day (15-min Ex) for 12 weeks. Left ventricular (LV) diameters were increased and ejection fractions decreased by echocardiography, and myocardial nitric oxide (NO) activity, measured by the in vitro MVO2 method, was reduced in both CS and MI rats compared with the sham. In CS rats, myocardial wall thickening fractions were not affected at 5 min of exercise, whereas they were reduced at 15 min of exercise, suggesting exercise-induced ischemia. Despite no changes in CS severity, the 5-min Ex increased CFR, ameliorated myocardial NO activity, attenuated left ventricular (LV) dysfunction and remodeling, reduced serum brain natriuretic peptide (BNP) levels, and improved survival, whereas the 15-min Ex aggravated LV dysfunction and remodeling. In contrast, neither of the exercise protocols improved these parameters in MI rats. CONCLUSIONS: Therapeutic responses to exercise differed in ischemic and infarcted hearts, partly via circulatory modulation downstream of the epicardial CS in relation to exercise-induced ischemia. When employing exercise for IHD, the causes of IHD, as well as the exercise protocols, need to be considered to achieve optimal effects.
Authors: Jhansi Dyavanapalli; Aloysius James Hora; Joan B Escobar; John Schloen; Mary Kate Dwyer; Jeannette Rodriguez; Christopher F Spurney; Matthew W Kay; David Mendelowitz Journal: Am J Physiol Heart Circ Physiol Date: 2020-05-15 Impact factor: 4.733
Authors: Musaad B Alsahly; Madaniah O Zakari; Lauren G Koch; Steven Britton; Laxmansa C Katwa; Robert M Lust Journal: Front Cardiovasc Med Date: 2021-11-26