Screening for Cardiac Magnetic Resonance Scar Features by 12-Lead ECG, in Patients with Preserved Ejection Fraction

Background: Increased QRS score and wide spatial QRS-T angle are independent predictors of cardiovascular mortality in the general population. Our main objective was to assess whether a QRS score ≥5 and/or QRS-T angle ≥105° enable screening of patients for myocardial scar features. Methods: Seventy-seven patients age ≤70 years with QRS score ≥5 AND/OR spatial QRS-T angle ≥105° as well as left ventricular ejection fraction (LVEF) >35% were enrolled in the study. All participants underwent complete clinical examination, signal averaged ECG (SAECG), 30-minute ambulatory electrocardiogram recording for T-wave alternans (TWA), and late gadolinium enhancement cardiac magnetic resonance (LGE-CMR). Relationship between QRS score, QRS-T angle with scar presence and pattern, as well as gray zone, core, and total scar size by LGE-CMR were assessed. Results: Myocardial scar was present in 41 (53%) patients, of whom 19 (46%) exhibited a typical ischemic pattern. QRS score but not QRS-T angle was related to total scar size and gray zone size (R² = 0.12, P = 0.002; R² = 0.17; P ≤ 0.0001, respectively). Patients with QRS scores ≥6 had significantly greater myocardial scar and gray zone size, increased QRS duration and QRS-T angle, a higher prevalence of late potentials presence, increased LV end-diastolic volume and decreased LVEF. There was a significant independent and positive association between TWA value and total scar (P = 0.001) and gray zone size (P = 0.01). Conclusion: Patients with preserved LVEF and myocardial scar by CMR also have electrocardiographic features that could be involved in ventricular arrhythmogenesis.