[Prevalence of electrocardiographical signs of right ventricular arrhythmogenic dysplasia].

Unlabelled: Right ventricular arrhythmogenic dysplasia (RVAD) is a state with high risk of sudden death in young patients. Early diagnosis of RVAD can facilitate sudden death prevention.

Aim: To assess prevalence of electrocardiographical signs of RVAD among children with "idiopathic" tachyarrhythmias.

Material: Patients without organic heart disease or overt noncardiac causes of arrhythmia aged 4-17 years (n=134, mean age 12+/-4.5 years, 56 girls and 76 boys) including 82 patients with >5000 extrasystoles VE 24 hours and 52 patients with ventricular tachycardia (VT). All patients had QTc interval <440 ms.

Methods: Twelve lead ECGs from all patients were analyzed for determination of morphology of arrhythmia and presence of "major" (epsilon wave and QRS duration >110 ms in V(1)-V(3)) and "minor" (VT with left bundle brunch block - LBBB, VE >1000/24 hours, T-wave inversion in V(2) and V(3)) diagnostic criteria for RVAD (W.McKenna, 1994; D.Corrado, 2000).

Results: ECG signs of RVAD were found in 28 of 58 (48.3%) of patients with VE and in 1 of 24 patients (4.2%) with atrial extrasystoles. Among patients with VE 27 (96.4%) had extrasystoles with LBBB morphology and 1 (3.6%) - with right bundle brunch block (RBBB) morphology. Combination of major and minor criteria sufficient for diagnosis of RVAD was found in 19% (8 of 42) of patients with VE with LBBB. Among 52 patients with VT 21 had polymorphic VT and 31 - monomorphic VT (16 with LBBB and 15 with RBBB). Epsilon wave was present in 56.3% (9/15) of patients with monomorphic VT and LBBB, in 4.8% (1/21) of patients with polymorphic VT and in none of the patients with monomorphic VT and RBBB. QRS duration exceeded 110 ms in 2 (12.5%), 2 (9.5%) and 0 patients among those with monomorphic VT and LBBB, polymorphic VT, and monomorphic VT and RBBB, respectively. Among patients with monomorphic VT and LBBB 37.5% (6/16) had combination of ECG criteria sufficient for diagnosis of RVAD. In 3 patients epsilon wave was registered in lead V(1) immediately prior to VT and disappeared after VT cessation. Implications. It can be suggested that presence of polymorphic VT or VE with LBBB morphology and specific ECG changes (first of all epsilon wave and QRS widening) distinguishes a group of patients with high risk of RVAD which requires thorough cardiological examination and dynamic observation.