[Cardiac rhythm disturbances in the children with hearing pathology]. / Narusheniya serdechnogo ritma u detei s patologiei slukha.

The aim of the study was to identify cardiac arrhythmias in children presenting with hearing impairments. Hearing loss in the children can occur concurrently with the disturbances of the cardiac rhythms. The detection of this pathology at the diagnostic stage is as important as it is at the stage of rehabilitation including surgical one. PATIENTS AND METHODS: A retrospective analysis of 100 patients (55 boys and 45 girls of the mean age of 4.8 years) operated in 2013 was made. RESULTS: Cardiac arrhythmias and conduction were recorded on the electrocardiograms obtained from 10 patients (4 boys and 6 girls) of the 100 examined ones, which amounted to 10%. The hereditary long QT syndrome (including Jervell-Lange-Nielsen syndrome) has not been identified. CONCLUSION: The timely diagnostics of congenital arrhythmias in the children with hearing impairment makes it possible to significantly reduce the risk of the sudden cardiac death (for example, in the patients presenting with the Jervell-Lange-Nielsen syndrome) and facilitates the choice of the anesthesiological support for the surgical treatment (including cochlear implantation) taking into consideration possible cardiac rhythm disturbances.

[Prevalence of electrocardiographical signs of right ventricular arrhythmogenic dysplasia]. / Rasprostranennost' élektrokardiograficheskikh priznakov aritmogennoi displazii pravogo zheludochka u bol'nykh s idiopaticheskimi zheludochkovymi takhiaritmiiami.

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.

[Comparison of QT-Interval Measurement Techniques and Their Clinical Value]. / Sravnenie sposobov izmereniia intervala Q-T i ikh klinicheskoe znachenie.

Long QT-interval is one of most important predictors of risk of development of life threatening arrhythmias and sudden death. Correct measurement of QT-interval is essential for diagnosis of its prolongation. At present the Bazett formula for calculation of corrected QT (QT(c) = QT/ radical (RR)) is a standard method of QT estimation. However historically in Russia calculation of predicted QT (QT(k) = k radical (RR)) QT(k) has become an accepted technique. Furthermore many authors in this country apply criteria created for QT(c) for interpretation of QT(k) values. This results in hyperdiagnosis of QT prolongation in unaffected persons, erroneous conclusions on harmless nature of this condition, and underestimation of risk in patients with real long QT syndrome. Thus it is vital to proclaim calculation of QT(c) an obligatory standard and to use existing international criteria for its interpretation.

[QT interval shortening in families with history of sudden death at young age]. / Ukorochenie intervala Q-T v sem'iakh s otiagoshchennym anamnezom po sluchaiam vnezapnoi smerti v molodom vozraste.

AIM: To assess frequency of short QT interval among members of families with history of young age sudden death. MATERIAL: Eleven children aged 3-16 years (mean age 11.2+/-4.2 years) from families with cases of sudden death at young age (<40 years) not caused by an obvious disease according to autopsy data. None of the probands had overt heart disease, life threatening arrhythmias, long QT syndrome. METHODS: Predicted QT value was estimated according to the P. Rautaharju formula [QT(p)=656/(1+HR/100)], and values equal to 80 and 88% of QT(p) (QT(p)80 and QT(p)88) were determined. Corrected QT interval duration (QT(c)) was calculated for all these values with the use of the Bazett formula. RESULTS: Values of corrected QT(c)88 370 ms and 350 ms were considered minimal for heart rates above and below 78 bpm, respectively. QT shortening to the level of QT(p)80 at heart rates above 70 bpm corresponded to QT(c) values <330 ms. Nine of 11 children (81.1%) had QT interval equal to or less than QT(p)88. Three probands with attacks of syncope had QT equal to QT(p)80, high concentration of sudden deaths in family (up to 30% of family members), and high prevalence of shortened QT <80% among family members. CONCLUSION: Shortened QT interval is characteristic for children with family history of sudden death at young age. Registration of QT duration equal to or shorter than 88% of predicted value requires exclusion of diseases and syndromes with increased risk of sudden death.

[Shortening of PR interval, bradycardia and polymorphic ventricular tachycardia--clinico-electrocardiografical syndrome with high risk of sudden death in children]. / Ukorochenie intervala P-R, bradikardiia i polimorfnaia zheludochkovaia takhikardiia--kliniko-élektrokardiograficheskii sindrom s vysokim riskom vnezapnoi smerti u detei.

AIM: To elucidate clinical and electrocardiographical characteristics of children and adolescents with malignant idiopathic polymorphic ventricular tachycardia. MATERIAL: Patients aged 6-14 years (n=16) with polymorphic bidirectional tachycardia registered either on standard 12-lead ECG (n=6), or during treadmill exercise test (n=2) and Holter ECG monitoring (n=8). None of the patients had overt heart or coronary artery disease, chronic extracardiac pathology or electrolyte disturbances. RESULTS: There was no QT, QT(s) prolongations, or ST segment elevations in right precordial leads. Eleven patients (68.8%) had shortening of PR interval -110 ms without signs of Wolf-Parkinson-White syndrome. All patients with shortened PR had history of syncopal states (9.1+/-9.2 per year), 4 patients (36.4%) had family history of sudden death in young age. Among patients without PR shortening 2 (40%) had history of syncopal attacks (1-2 or 0.6+/-0.89 per year). All patients with short PR had bradycardia while in sinus rhythm (55.5+/-9.1 bpm compared with 78.1+/-2.8 bpm in patients without PR shortening). CONCLUSION: Shortened PR and bradycardia were found to be associated with frequent attacks of syncope in this series of children with polymorphic tachycardia. Therefore combination of short PR, bradycardia and polymorphic ventricular tachycardia was suggested to comprise clinico-electrocardiographic syndrome with high risk of malignant ventricular tachyarrhythmia and sudden death.

[Circadian structure of cardiac rhythm in tachyarrhythmia]. / Sutochnaia struktura ritma serdtsa pri takhiaritmiiakh.

AIM: To determine clinical implication of changes in the structure of circadian cardiac rhythm in patients with tachyarrhythmia basing on estimation of the circadian index (CI). MATERIAL AND METHODS: 24-h Holter monitoring was conducted in 154 patients aged 4 to 18 years: 125--with supraventricular paroxysmal tachycardia, 13--with long Q-T interval, 16--with idiopathic ventricular tachycardia. CI was calculated as mean day heart rate (from 7.00 to 22.00)/mean night heart rate (from 23.00 to 6.00). RESULTS: Patients with long Q-T interval had less CI while those with supraventricular paroxysmal and idiopathic ventricular tachycardia had higher CI vs normal values. CI changes became more pronounced with growing disease severity. CONCLUSION: Cardiac arrhythmia with low CI is associated with progressive vegetative denervation while that with high CI occurs in increased cardiac sensitivity to sympathetic impacts.