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33rd International Congress on Electrocardiology

International Society of Electrocardiology

Dynamics Of Heart Rate Variability On A Background Of Beta-Blockers Therapy - New Factor Of Prediction Of Syncope Recurrence And Stratification Of Risk Of Sudden Cardiac Death In Patients With Long Qt Syndrome?

Meeting Abstract

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  • corresponding author presenting/speaker S. Chuprova - Russian Center of Children`s Arrhythmias, Moscow, Russland

33rd International Congress on Electrocardiology. Cologne, 28.06.-01.07.2006. Düsseldorf, Köln: German Medical Science; 2007. Doc06ice132

The electronic version of this article is the complete one and can be found online at:

Published: February 8, 2007

© 2007 Chuprova.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



The purpose of the study: to assess value of dynamics of heart rate variability (HRV) on a background of beta-blockers therapy for prediction of development or syncope recurrence and SCD in patients (pts) with LQTS.

Methods and results: diurnal Holter monitoring was conducted in 50 children with LQTS (64% pts with syncope) before and on beta-blockers therapy (atenolol). HRV was evaluated by time-domain analysis. In pts, who had recurrence of syncope (24%) and suddenly died (4%), comparison of changes of HRV with the development of the given events was conducted. Before treatment of beta –blockers in 46,9% pts with syncope (in the anamnesis) and 50% pts without syncope a decrease of HRV was observed but after assignment of beta-blockers – in 37,5% and 27,8% pts accordingly. After increase of diurnal beta-blockers doses a decrease of HRV had only 18,8% pts with syncope (12,5% pts had syncope recurrence) and 11,1% pts without syncope. In 15,6% pts a decrease of HRV was observed before syncope recurrence and in 4% pts – before SCD. At analyses of dynamics of HRV on a background of beta-blockers therapy (during the observation period - 6,5±1,8 years) in pts with bad prognosis of the disease (syncope recurrence, SCD) three types of trends of HRV were discovered (1 – normal of HRV before prescription of beta-blockers, its increase on beta-blockers with its further considerable decrease; 2 – initially decreased HRV with absence of dynamics despite full beta-blockers dose; 3 – initially decreased HRV with normalization on beta-blockers and its further considerable decrease).

Conclusions: Taking into account a possibility of change of prescribed device of beta-adrenoreceptors under the influence of beta-blockers, a dynamic assessment of HRV in pts with LQTS with correction (if necessary) of diurnal beta-blockers doses. The most unfavorable prognostic factor of development and recurrence of syncope and SCD in pts with LQTS is not the presence of initially (before treatment) decreased HRV, but its decrease against a background of adequate beta-blockers treatment with absence of dynamics at enforcement of therapy (increase of diurnal beta-blockers doses). Considerable decrease of HRV with absence of its dynamics against a background of increase of diurnal beta-blockers dose in pts with LQTS is probably indication for consultation with cardio surgeon (implantation of ICD and/or conduct of LCSD). Sudden decrease of HRV with absence of dynamics of indices at increase of diurnal beta-blockers dose can probably be considered as new factor of stratification of risk of SCD in pts with LQTS which requires further study.