RESUMO
BACKGROUND: Cardiac rehabilitation is a combination of integrated programs aimed at improving outcomes in patients recovering from heart events. OBJECTIVES: The present study aimed to evaluate the early benefits of supervised exercise training on electrophysiological function of post-ischemic myocardium. In this regard, signal-averaged electrocardiogram (SAECG) was used. PATIENTS AND METHODS: Between May and September 2012, all patients (n = 100) admitted to our center, with the diagnosis of acute Myocardial Infarction (MI), were enrolled in this study. Every other patient was assigned to two groups receiving either inpatient cardiac rehabilitation plus standard post-MI care (cases) or only standard post-MI care (controls). Electrophysiological function was assessed by SAECG in all the patients at baseline and on the day 5. The patients were considered as having late potential if they had abnormalities in at least two SAECG indices. RESULTS: Cardiac rehabilitation led to significant improvements in QRS duration (P < 0.001), square root of amplitude in the last 40 ms (P < 0.001) and duration of terminal signal with low amplitude (P < 0.001). Cardiac rehabilitation also resulted in amelioration of SAECG parameters; frequency of patients with late potential significantly decreased from 64% to 20% after five days (P < 0.001). CONCLUSIONS: Supervised in-hospital exercise training was associated with improvements in SAECG-measured electrical activity post-MI.
RESUMO
BACKGROUND: It has been suggested that the autonomic system function and the metabolic syndrome can significantly affect patients' survival. The aim of the current study was to investigate the impact of the cardiac rehabilitation program on the autonomic system balance in patients with coronary artery disease. METHODS: Patients with a previous diagnosis of coronary artery disease who were referred to the Cardiovascular Rehabilitation Center of Afshar Hospital (Yazd, Iran) between March and November 2011 were enrolled. All the patients participated in rehabilitation sessions 3 times a week for 12 weeks. Heart rate recovery (HRR) was measured as an indicator of the autonomic system balance. In order to calculate HRR, the maximum heart rate during the exercise test was recorded. At the end of the exercise test, the patients were asked to sit down without having a cooldown period and their heart rate was recorded again after 1 minute. The difference between these 2 measurements was considered as HRR. RESULTS: A total of 108 patients, including 86 (79.6%) men and 22 (20.4%) women, completed the rehabilitation course. The mean age of the study participants was 58.25 ± 9.83 years. A statistically significant improvement was observed in HRR (p value = 0.040). Significant declines were also observed in the patients' waist circumference (p value < 0.001) and systolic and diastolic blood pressures (p value = 0.018 and 0.003, respectively). A decreasing trend was observed in the patients' body mass index, but it failed to reach statistical significance (p value = 0.063). No statistically meaningful changes were noted in fasting blood glucose (p value = 0.171), high-density lipoprotein (p value = 0.070), or triglyceride concentrations (p value = 0.149). CONCLUSION: The cardiac rehabilitation program may help to improve HRR and several components of the metabolic syndrome in patients with coronary heart disease.