Impact of cardiac rehabilitation on ventricular repolarization indices following coronary artery bypass grafting

Background: The aim of this study was to evaluate the effect of cardiac rehabilitation on electrocardiographic changes in patients undergoing isolated coronary artery bypass grafting. Methods: Between January 2016 and July 2019, a total of 625 patients (485 males, 140 females; mean age: 59.6 years; range, 50.6 to 68.6 years) who underwent isolated coronary artery bypass grafting and survived were retrospectively analyzed. The patients were divided into two groups according to the participation in the cardiac rehabilitation program as follows: the Rehab(+) group (n=363) and the Rehab(-) group (n=262). Electrocardiographic parameters of both groups were compared. Results: There was a significant decrease in the electrocardiographic findings of heart rate (p<0.001), QTc (p<0.001), Tpe duration (p<0.001), Tpe/QT ratio (p<0.001), and Tpe/QTc ratio (p<0.001) in the Rehab(+) group before and after surgery. There was a significant decrease in the Rehab(+) group, compared to the Rehab(-) group, in terms of parameters of QT interval (p=0.001), QTc (p= 0.017), Tpe duration (p<0.001), Tpe/QT ratio (p<0.001), and Tpe/QTc ratio (p<0.001). Conclusion: Cardiac rehabilitation program after coronary artery bypass grafting decreases ventricular repolarization indices of electrocardiography. Based on these changes, postoperative cardiac rehabilitation program may reduce the risk of ventricular arrhythmia and sudden cardiac death during follow-up.