Key result
Aerobic exercise training prior to myocardial infarction in rats prevented left ventricular systolic dysfunction and attenuated cardiac autonomic impairment compared to sedentary controls.
Why the study?
Does aerobic exercise training prior to myocardial infarction prevent cardiac dysfunction and autonomic impairment in rats?
Does aerobic exercise training prior to myocardial infarction prevent cardiac dysfunction and autonomic impairment in rats?
Absolute Event Rate: 38% vs 30%
p-value: p=<0.05
Exercise training prior to myocardial infarction in rats attenuates cardiac dysfunction, which is associated with the prevention of cardiac autonomic impairment.
Pre-MI aerobic training attenuated dysfunction in rats; leaves open translation to human prevention strategies.
BACKGROUND: It has been suggested that exercise training (ET) protects against the pathological remodeling and ventricular dysfunction induced by myocardial infarction (MI). However, it remains unclear whether the positive adjustments on baroreflex and cardiac autonomic modulations promoted by ET may afford a cardioprotective mechanism. The aim of this study was to evaluate the effects of aerobic ET, prior to MI, on cardiac remodeling and function, as well as on baroreflex sensitivity and autonomic modulation in rats. METHODS: Male Wistar rats were divided into 4 groups: sedentary rats submitted to Sham surgery (C); trained rats submitted to Sham surgery (TC); sedentary rats submitted to MI (I), trained rats submitted to MI (TI). Sham and MI were performed after ET period. After surgeries, echocardiographic, hemodynamic and autonomic (baroreflex sensitivity, cardiovascular autonomic modulation) evaluations were conducted. RESULTS: Prior ET prevented an additional decline in exercise capacity in TI group in comparison with I. MI area was not modified by previous ET. ET was able to increase the survival and prevent additional left ventricle dysfunction in TI rats. Although changes in hemodynamic evaluations were not observed, ET prevented the decrease of baroreflex sensitivity, and autonomic dysfunction in TI animals when compared with I animals. Importantly, cardiac improvement was associated with the prevention of cardiac autonomic impairment in studied groups. CONCLUSIONS: Prior ET was effective in changing aerobic capacity, left ventricular morphology and function in rats undergoing MI. Furthermore, these cardioprotective effects were associated with attenuated cardiac autonomic dysfunction observed in trained rats. Although these cause-effect relationships can only be inferred, rather than confirmed, our study suggests that positive adaptations of autonomic function by ET can play a vital role in preventing changes associated with cardiovascular disease, particularly in relation to MI.
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Rodrigues et al. (2014) studied Myocardial infarction (n=38). Aerobic exercise training vs. Sedentary lifestyle was evaluated on Fractional shortening (%) (p=<0.05). Aerobic exercise training prior to myocardial infarction in rats prevented left ventricular systolic dysfunction and attenuated cardiac autonomic impairment compared to sedentary controls.