Relationship Between Electrocardiographic Findings and Cardiac Magnetic Resonance Phenotypes in Arrhythmogenic Cardiomyopathy

Background-The new designation of arrhythmogenic cardiomyopathy defines a broader spectrum of disease phenotypes, which include right dominant, biventricular, and left dominant variants. We evaluated the relationship between electrocardiographic findings and contrast-enhanced cardiac magnetic resonance phenotypes in arrhythmogenic cardiomyopathy. Methods and Results-We studied a consecutive cohort of patients with a definite diagnosis of arrhythmogenic cardiomyopathy, according to 2010 International Task Force criteria, who underwent electrocardiography and contrast-enhanced cardiac magnetic resonance. Both depolarization and repolarization electrocardiographic abnormalities were correlated with the severity of dilatation/dysfunction, either global or regional, of both ventricles and the presence and regional distribution of late gadolinium enhancement. The study population included 79 patients (60% men). There was a statistically significant relationship between the presence and extent of T-wave inversion across a 12-lead ECG and increasing values of median right ventricular (RV) end-diastolic volume (P<0.001) and decreasing values of RV ejection fraction (P<0.001). The extent of T-wave inversion to lateral leads predicted a more severe RV dilatation rather than a left ventricular involvement because of the leftward displacement of the dilated RV, as evidenced by contrast-enhanced cardiac magnetic resonance. A terminal activation delay of > 55 ms in the right precordial leads (V1-V3) was associated with higher RV volume (P=0.014) and lower RV ejection fraction (P=0.053). Low QRS voltages in limb leads predicted the presence (P=0.004) and amount (P<0.001) of left ventricular late gadolinium enhancement. Conclusions-The study results indicated that electrocardiographic abnormalities predict the arrhythmogenic cardiomyopathy phenotype in terms of severity of RV disease and left ventricular involvement, which are among the most important determinants of the disease outcome.