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Published on: March 27, 2018
Effect of exercise-based cardiac rehabilitation following coronary artery bypass surgery on ventricular
Ali Vasheghani-Farahani1, Leila Asef-Kabiri, Farzad Masoudkabir
1Department of Cardiology, Tehran Heart Center, Jalal al-Ahmad CrossTehran, Iran. avasheghani@sina.tums.ac.ir
Insights
Exercise-based cardiac rehabilitation significantly reduced ventricular repolarization heterogeneity in patients after coronary artery bypass surgery. This improvement in QT interval dispersion (QTd) and heart rate-corrected QTd (QTc-d) was not observed in the control group.
Area of Science:
- Cardiology
- Exercise Physiology
- Clinical Research
Background:
- Ventricular repolarization heterogeneity is linked to arrhythmias and sudden cardiac death.
- Assessing these indices is crucial for risk stratification in cardiac patients.
Purpose of the Study:
- To evaluate the impact of exercise-based cardiac rehabilitation (CR) on ventricular repolarization heterogeneity.
- To assess changes in QT interval dispersion (QTd), RR interval variability (RRV), and heart rate-corrected QTd (QTc-d) post-coronary artery bypass surgery (CABGS).
Main Methods:
- A cohort study involving 122 patients post-CABGS.
- Two groups: CR group (≥15 sessions) and control group (≤5 sessions).
- Electrocardiograms measured QTd, RRV, and QTc-d pre-surgery, at CR initiation, and post-CR program.
Main Results:
- The CR group demonstrated significant reductions in QTd (-49.4%) and QTc-d (-52.8%) (P < .0001).
- No significant changes in QTd, QTc-d, or RRV were observed in the control group.
- CR was an independent predictor of improved QTd and QTc-d after adjusting for clinical variables.
Conclusions:
- Exercise-based cardiac rehabilitation programs effectively improve ventricular repolarization heterogeneity in CABGS patients.
- CR offers a significant benefit in reducing repolarization abnormalities.
- These findings support the integration of CR into post-surgical cardiac care.
Purpose:
Indices of ventricular repolarization heterogeneity are associated with future arrhythmias and sudden cardiac death. We investigated the effect of exercise-based cardiac rehabilitation (CR) on these indices in a sample of Iranian patients.
Methods:
Patients (N 122), who had undergone coronary artery bypass surgery (CABGS), were enrolled in this cohort study. Sixty patients attended 15 or more sessions of CR (CR group) and the remaining 62 patients attended 5 or fewer sessions of CR (control group). A standard 12-lead electrocardiogram was recorded for each patient. QT interval dispersion (QTd), RR interval variability (RRV), and heart rate-corrected QTd (QTc-d) were measured 3 times as follow: just before surgery, at the beginning of the first session of the CR program, and at the end of the 15th session for the CR group or the last session for the control group.
Results:
Following completion of the exercise-training program, the CR group showed a significant decrease in QTd (Δ = -49.4%, P < .0001) and QTc-d (Δ = 52.8%, P .0001), but not in the control group (Δ = 13.4% and 17.9%, respectively, P > .05 for both). In both groups, no statistically significant change in RRV was observed. After adjustment for variables such as age, gender, digoxin use, β-blocker use, and prerehabilitation ejection fraction, CR remained the independent predictor of QTd and QTc-d.
Conclusion:
Results suggest that cardiac rehabilitation and exercise training programs significantly improve the indices of ventricular repolarization heterogeneity in patients with coronary artery disease who received CABGS.
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