RESUMO
BACKGROUND: The two predominant etiologies of right ventricular tachycardia (VT) are arrhythmogenic right ventricular cardiomyopathy (ARVC) and idiopathic VT arising from the right ventricular outflow tract (RVOT). Discrimination between these two entities is critical, as their prognoses and therapeutic options differ. The Tpeak -Tend (Tpe) interval reflects the transmural repolarization dispersion and its prolongation is associated with high mortality. METHODS: We compared the sinus rhythm electrocardiogram (ECG) of 43 patients (24 male, 43 ± 16 years) with VT originating from right ventricle. Five patients under antiarrhythmic drug therapy were excluded. Tpe interval was measured in each precordial leads and compared among patients with ARVC and RVOT-VT. RESULTS: Twenty-five patients (16 male, 42 ± 16 years) met the Task Force criteria for the diagnosis of ARVC, and 13 patients (seven male, 45 ± 14 years) had idiopathic RVOT tachycardia. Patients with ARVC had significantly prolonged Tpe intervals in all precordial leads compared to patients with idiopathic RVOT VT (137.1 ± 32.6 ms vs 93.8 ± 16.9 ms; P < 0.001 in V1, 133.2 ± 35.5 ms vs 104.7 ± 16.9 ms; P = 0.01 in V2, 125.7 ± 31.5 ms vs 99.1 ± 19.6 ms; P = 0.09 in V3, 121.9 ± 26.5 ms vs 92.3 ± 19.7 ms; P = 0.001 in V4, 123.1 ± 26.5 ms vs 99.5 ± 20:1 ms; P = 0.04 in V5 and 126.9 ± 32.2 ms vs 89 ± 11.3 ms; P < 0.001 in V6, respectively). For the diagnosis of ARVC, Tpe cut-off value of 97 ms in V1 had 84% sensitivity and 62% specificity (area under curve = 0.880). CONCLUSION: In patients with VT of RV origin, the prolonged Tpe interval in sinus rhythm electrocardiogram supports the diagnosis of ARVC.