Cardiac Rehabilitation Improves the QRS Fragmentation in Patients With ST Elevation Myocardial Infarction

Introduction: We aimed to evaluate the effect of exercise-based cardiac rehabilitation (CR) on the fragmented QRS (fQRS) in patients with ST elevation myocardial infarction (STEMI). Methods: Ninety-seven patients with STEMI participated CR and 81 patients as a control group were included to the study. The trained patients were grouped according to the presence and persistence of QRS fragmentation on the electrocardiogram (ECG) before and after CR. If the fragmentation was present on the ECG at the beginning of the CR but not on the ECG at the end of CR; the transient group, if the fQRS persists after CR; the persistent fQRS group. ECGs obtained from the control group were grouped according to the presence of a fQRS on ECG. Results: Among the trained patients, 45 (46%) did not have a fQRS before CR, whereas 52 (54%) presented a fQRS before CR, which was persistent in 35 patients (the persistent fQRS group) and transient in 17 patients (the transient fQRS group). Among 81 patients included in the control group, fQRS was persistent in 41 patients. Presence of fQRS on the ECG was significantly decreased with CR and it is better in trained group than the control group (P = .034). There were not significant correlations with other characteristics, except hypertension. Conclusion: The existence of the fQRS decreases after CR in patients with STEMI especially in hypertensive individuals, which may be related to improved electrical stability in the myocardium as a predictor of increase in survival and decrease in major cardiac events.