Efficacy of moderate exercise training on heart rate variability and left ventricular remodeling after myocardial infarction

Abstract

Background After myocardial infarction (MI), elevated sympathetic activity and/or reduced parasympathetic activity are observed. As a result, these patients have a decreased heart rate variability (HRV), which has been linked to an elevated risk of adverse effects and death. Following MI, the remodeling of the left ventricle (LV) is a complex and multifactorial mechanism, with therapeutic and prognostic consequences. Medications that reduced LV improved survival and standard of living. Aim We aimed to evaluate the effect of continuous exercise remodeling training on HRV, function capacity [6-min walk test (6MWT)], and LV remodeling in patients who had experienced MI. Patients and methods One month after having MI, 40 eligible male patients aged 45–55 years old were recruited. Patients underwent a supervised intensive CR recovery program consisting of continuous aerobic exercise. Evaluation of the effect of this program was done by clinical examination, transthoracic echocardiography to calculate ejection fraction, 6MWT, and Holter ECG 24 h to measure different HRV parameters. All patients received 36 training sessions (three times/week for 12 weeks). The results of these procedures were compared before and after this program. Results According to the current results, the mean pretreatment and posttreatment 6MWT values were 208.65 ± 24.62 and 360.98 ± 109.78, respectively, with an improvement percentage of 55.79%. Irrespective of time or frequency domain, HRV parameters were markedly improved after treatment compared with pretreatment values. Ejection fraction % was significantly improved by 14.82%. Conclusion Exercise training tends to be a beneficial clinical technique for patients with MI who have an unbalanced autonomic function, which is manifested by improvement of HRV parameters. Exercise training improves blood pressure and resting heart rate. Improvement of 6MWT parameters occurred after exercise training.

Keywords

• exercise training
• heart rate variability
• left ventricle remodeling
• myocardial infarction