QRS Fragmentation in 12-lead Surface ECG as a Predictor of Myocardial Viability Assessed by Dobutamine Stress Echocardiography in Patients with Ischemic Left Ventricular Systolic Dysfunction

Background: Worldwide, coronary artery disease (CAD) continues to be a major cause of death. Assessment of myocardial viability in patients with ischemic left ventricular (LV) systolic dysfunction is reasonable to guide revascularization management. Fragmented QRS (fQRS) on a 12-lead surface electrocardiogram (ECG) has been associated with cardiac scarring and conduction abnormalities. This study investigated the role of fQRS in predicting myocardial viability using dobutamine stress echocardiography (DSE) as a reference. Materials and Methods: Eighty patients with ischemic LV systolic dysfunction were enrolled. Based on resting ECG, patients were divided into two groups: those with and without fQRS. Clinical assessment, transthoracic echocardiography, and low-dose DSE were performed on all patients. Results: Patients with fQRS showed significantly lower myocardial viability (14% vs. 70%, P < 0.001), a lower improvement in Wall Motion Score Index (16.22% vs. 24.85%, P < 0.001), and a reduced stress left ventricular ejection fraction (39.86% vs. 44.86%, P < 0.001). fQRS in the anterior leads showed a sensitivity of 65%, specificity of 95%, and a negative predictive value (NPV) of 89.1% for detecting nonviability in the left anterior descending artery (LAD). fQRS in nonanterior leads showed a sensitivity of 72.7%, specificity of 65.2%, and NPV of 93.75% for detecting nonviability in the left circumflex artery and/or right coronary artery. Conclusions: FQRS on a resting ECG is associated with decreased myocardial viability, especially in the LAD territory. Although fQRS shows a high NPV to rule out myocardial viability, its diagnostic accuracy remains limited, suggesting that fQRS cannot replace advanced imaging modalities.