Impact of Revascularization on Cardiac Electrical Activity in Patients with Ischemic Left Ventricular Dysfunction

Background: Ischemic heart disease is a leading cause of heart failure worldwide. Coronary revascularization by percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) restores myocardial perfusion and may improve electrical stability in patients with ischemic left ventricular dysfunction. Corrected QT interval and heart rate variability are established predictors of arrhythmic risk and mortality. Objectives: To evaluate the effect of coronary revascularization on cardiac electrical activity using surface ECG and 24-hour Holter monitoring in patients with ischemic left ventricular dysfunction. Methods: In this prospective, non-randomized study, 80 patients with EF <50% were allocated to a revascularization group (PCI or CABG; n=40) or a medical therapy group (n=40). ECG and 24-hour Holter monitoring were performed at baseline and one month post-intervention. Results: Revascularization significantly reduced corrected QT interval (432.4 ± 23.9 ms vs. 427.3 ± 23.1 ms; P = 0.003) and QT dispersion, with a greater decrease than medical therapy (P < 0.001 vs. P = 0.035). Heart rate variability improved markedly after revascularization (P < 0.001). Non-sustained ventricular tachycardia observed at baseline resolved completely in all affected patients (P = 0.024). Conclusions: Revascularization was associated with improvements in ECG markers of electrical stability, including corrected QT interval (P = 0.003), QT dispersion (P < 0.001), and heart rate variability (P < 0.001), with complete resolution of NSVT (P = 0.024). These findings suggest enhanced myocardial electrical stability; however, medication adjustments and residual ischemia may have influenced outcomes. Further studies are needed to clarify causal relationships and long-term prognostic impact