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To assess parameters of heart rate turbulence in patients with ventricular extrasystoles (VES).Patients with VES during Holter ECG monitoring (n=65, age 1-17 years, 32 girls, 33 boys) including 3 with long QT syndrome, 4 with catecholaminergic ventricular tachycardia, 1 with arrhythmogenic right ventricular dysplasia, 4 with dilated cardiomyopathy, 2 with Brugada syndrome, 3 with Duchenne myopathy, and 48 with idiopathic VES. Parameters HRT onset and slope were calculated for 1678 VES. During follow-up (6+/-4.9 years) deaths, sudden deaths, and such complications as syncope, cardiac dilatation, heart failure were registered in 26 patients.HRT slope exceeded 2.5 ms/RR in all patients. HRT onset was0 in patients with catecholaminergic ventricular tachycardia, dilated cardiomyopathy, and Duchenne myopathy. The following complications occurred in 7 of 8 patients (87.5%) with HRT onset0: syncope, sudden deaths (2 patients with dilated cardiomyopathy), dilatation of cardiac chambers, tolerance to antiarrhythmic therapy. Patients with long QT syndrome and arrhythmogenic right ventricular dysplasia (including 2 who afterwards died suddenly) had normal HRT onset. The sensitivity and specificity of HRT onset measurement for unfavorable prognosis of VES was 27 and 97%, respectively. No relationship was found between HRT slope and onset (r=-0.057).Pathological HRT (mainly represented by changes of HRT onset) are characteristic for organic myocardial diseases. Therefore detection of abnormal HRT dictates necessity of exclusion of organic cardiac pathology.

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.To assess prevalence of electrocardiographical signs of RVAD among children with "idiopathic" tachyarrhythmias.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 with5000 extrasystoles VE 24 hours and 52 patients with ventricular tachycardia (VT). All patients had QTc interval440 ms.Twelve lead ECGs from all patients were analyzed for determination of morphology of arrhythmia and presence of "major" (epsilon wave and QRS duration110 ms in V(1)-V(3)) and "minor" (VT with left bundle brunch block - LBBB, VE1000/24 hours, T-wave inversion in V(2) and V(3)) diagnostic criteria for RVAD (W.McKenna, 1994; D.Corrado, 2000).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.