The Diagnostic and Prognostic Value of the 12-Lead ECG in Arrhythmogenic Left Ventricular Cardiomyopathy

Background: Electrocardiographic findings in arrhythmogenic left ventricular cardiomyopathy (ALVC) have been limited to small studies. Objectives: The authors aimed to analyze the electrocardiogram (ECG) characteristics of ALVC, to correlate ECG with cardiac magnetic resonance and genetic data, and to evaluate its prognostic value. Methods: We reviewed data of 125 consecutive patients with ALVC (81.5% desmoplakin pathogenic/likely pathogenic variants). The composite endpoint of major arrhythmic events (MAEs) included sudden cardiac death, aborted sudden cardiac death, and appropriate implantable cardioverter-defibrillator shock. Predictors of MAE were evaluated with logistic regression. Results: ALVC showed distinct ECG signs, including left posterior fascicular block (LPFB) (13.6%), pathological Q waves (26.4%), R/S ratio in V1 ≥0.5 (26.4%), and SV1 + RV6 ≤12 mm and RI + RII ≤8 mm (44%). Fifteen (12%) patients had a normal ECG. MAE occurred in 35 patients (28%). In multivariable analysis, LPFB (OR: 4.7; 95% CI: 1.2-18.3), syncope (OR: 84.95; 95% CI: 14-496), transmural late gadolinium enhancement (OR: 9.95; 95% CI: 2.3-36), and right ventricular ejection fraction (OR: 0.92; 95% CI: 0.87-0.97) were the independent predictors of MAE. The model including these 4 variables achieved a remarkable predictive capability (area under the curve: 0.9). In the primary prevention scenario, with Cox regression, LPFB (HR: 3.98; 95% CI: 1.3-12.0), syncope (HR: 19.13; 95% CI: 5.8-63.0), and transmural late gadolinium enhancement (HR: 10.57; 95% CI: 2.9-38.0) were independent predictors of MAE. Conclusions: In ALVC, ECG is a valuable diagnostic tool and may have a relevant prognostic role, since LFPB is a strong and independent predictor of MAE.