Differentiating arrhythmogenic right ventricular cardiomyopathy from right ventricular outflow tract ventricular tachycardia using multilead QRS duration and axis

BackgroundVentricular tachycardia (VT) resulting from arrhythmogenic right ventricular cardiomyopathy (ARVC) may be difficult to differentiate from idiopathic right ventricular outflow tract (RVOT) VT.ObjectivesThe purpose of this study was to investigate the hypothesis that QRS characteristics would be different in ARVC because of altered conduction through abnormal myocardium.MethodsIn 24 RVOT VT patients (18 women and 6 men; age 42 ± 10 years) and 20 ARVC patients (12 women and 8 men; age 38 ± 14 years), mean QRS duration, frontal plane axis, and precordial R-wave transition were measured in 12-lead ECGs recorded during VT.ResultsMean QRS duration was longer in all 12 leads in ARVC patients. A significant difference was noted in leads I, III, aVL, aVF, V1, V2, and V3 (P <.05). Leads I and aVL had the largest mean difference between ARVC and RVOT VT patients of 17.6 ± 4.7 ms and 15.8 ± 7.5 ms, respectively (P <.0001). Lead I QRS duration ≥120 ms had a sensitivity of 100%, specificity 46%, positive predictive value 61%, and negative predictive value 100% for ARVC. The area under the receiver operating characteristic (ROC) curve was 0.89. The addition of mean QRS axis <30° (R