Aim. To present the experience and assess the complications of permanent pacing in children with bradyarrhythmias based on long-term follow-up.Methods. Data of 145 children with structurally normal heart with implanted pacemakers at the age from 1 month to 18 years were retrospectively assessed. The follow-up was from 1999 to 2020 years. Epicardial pacemaker was implanted in 71 children, endocardial - in 74. The mean age of the primary implantation was 8.67±5.2 years.Results. The following complications were disclosed: hemodynamic complications (heart chamber enlargement in dynamics and/or development of dyssynchrony, the appearance and increase in the regurgitation degree on the atrioventricular valves), bacterial endocarditis, hemopericardium, subclavian vein occlusion, pericarditis, infection of the pacemaker and its pocket, leads dislocation and fracture. With epicardial pacing various complications were detected in 24 (33.8%) examined patients, with endocardial - in 37 (50%). Hemodynamic complications with epicardial permanent pacing are associated with intraventricular dyssynchrony due to implantation of a ventricular lead on the lateral wall or the right ventricular outflow tract. Hemodynamic complications were not recorded in patients that performed the implantation of an epicardial lead at the left ventricular (LV) apex.Conclusion. Children with pacemakers require careful follow-up. The most rational is the use of a primary epicardial pacemaker system with lead implantation on the apex of the LV. Such approach allows the veins to be preserved for endocardial stimulation at an older age, and to prevent hemodynamic complications. Neither epicardial nor endocardial pacemaker implantation guarantee the absence of complications. However, compliance with the above conditions will allow achieving high efficiency and safety of cardiac stimulation in children.

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Aim: To evaluate the electrical activity of the myocardium and the radiofrequency (RF) application zone resulting from radiofrequency ablation (RFA) performed at an early age.Material and Methods. A prospective follow-up study included three patients who underwent intracardiac electrophysiological study (EPS) and effective RFA of the tachycardia for the first time at an early age. A reintervention was required in one case 12 years after the procedure and in two cases six years after it due to recurrent and new-onset arrhythmias. During the reintervention, electroanatomical mapping was performed to assess the potential damaging effect of radiofrequency exposure in the area of the first ablation.Results. The intracardiac EPS and amplitude bipolar CARTO-reconstruction of primary ablation area were performed during repeated RFA procedure. The study showed that neither zones with a decrease in the amplitude of electrical signal from the myocardium nor silent electrical zones were present ruling out the cicatricial-sclerotic changes in the myocardium in children in the long-term period after RF exposure.Conclusion. The study showed that no increase in the coagulation necrosis zone in the area of primary ablation occurred during the growth of child when the sparing energy and temperature parameters of RFA and the limited number of RF applications were used. Further research in this area is required.

Первичные кардиомиопатии в детском возрасте представляют собой редкое, но серьезное заболевание, которое является частой причиной сердечной недостаточности и наиболее частой причиной трансплантации сердца у детей старше 1 года. За последние десятилетия диагностика кардиомиопатии продвинулась от традиционных клинических подходов к новым генетическим и визуализационным методам. В статье представлен обзор литературных данных о современной классификации первичных педиатрических кардиомиопатий, особенностях клинического течения и визуализации, которая является неотъемлемой частью диагностики на основе первичного морфофункционального фенотипа.

Introduction In some cases accessory pathway-mediated ventricular preexcitation can be associated with electro-mechanical dyssynchrony and, consequently, with dyssynchrony-related dilated cardiomyopathy, even in the absence of supraventricular tachycardia (SVT). Sometimes rapid progression of ventricular dysfunction developed in such patients after birth. Methods and materials 8 patients with asymptomatic WPW and dyssynchronous cardiomyopathy were examined in our Institute from 2017 till 2019. Four patients of the group were observed in other clinics with dilated cardiomyopathy (DCM) and prescribed appropriate therapy without significant clinical effect. The absence of complaints of heartbeat and episodes of tachycardia at the scheduled Holter monitoring allowed eliminating incessant tachycardia as a possible cause of cardiomyopathy. After radiofrequency ablation (RFA) all patients were performed ECG to assess QRS duration, Holter monitoring, echocardiography (Echo) for assessment of heart chamber volume and left ventricle (LV) contractile function and Speckle tracking – Echo with LV longitudinal strain assessment. The average age of the patients was 9.5 years (from 2 to 14 years). 6 children had heart failure (NYHA Class II). Results According to Echo all patients had widened QRS complex. Dilatation and enlargement of LV volume were marked in 6 pts. According to Echo7 patients had decrease of LV contractile function. According to Speckle tracking – Echo all patients had intraventricular dyssynchrony, decrease of longitudinal strain indices. At intracardiac electrophysiology study right-sided accessory pathways was diagnosed in all patients, successful RFA was performed. Preexitation relapsed, and the repeated RFA was performed in 2 pts. Complications caused by RFA were not marked. After RFA all patients showed a regular normalization of QRS duration. At the 5th day after RFA Echo was performed to all patients. The patients with initially decreased LV ejection fraction had it increased. The patients with initial dilatation and LV volume enlargement had normalization of the given indices. According to Speckle tracking – Echo normalization of global and regional myocardial function, LV longitudinal strain, disappearance of intraventricular and interventricular dyssynchrony were marked in all patients. The index of longitudinal strain was 17,0±0,64% before RFA, after RFA - 23,75±0,92% (p=0,ehab724.035946). Conclusion As a result of RFA of accessory pathways electromechanical resynchronization causes LV demodeling and restoration of its contractile ability. The presented clinical examples are an additional indication for RFA of accessory pathways even in the absence of SVT in patients regardless of age. FUNDunding Acknowledgement Type of funding sources: None.

Background. Currently pacing is the only treatment option for life-threatening bradyarrhythmias. Considering the specific factors of pediatric patients, specialists in this field should be highly professional.Aim: To present the experience and retrospective analysis of complications of permanent pacing in children and adolescents from Tomsk National Research Medical Center.Material and Methods. Complications of permanent pacing in children with structurally normal heart and children with congenital heart defects were analyzed. The follow-up was from 1999 to 2021 years. 256 patients aged from 1 month to 18 years participated in the study. Epicardial pacemaker was implanted in 173 children, endocardial – in 83 patients. Average time from primary implantation to complications was 2.1 ± 2.7 years.Results. Hemodynamic complications are the most common among patients with epicardial and endocardial permanent pacing. Hemodynamic complications with epicardial permanent pacing are associated with intraventricular dissynchrony due to stimulation in the area of the lateral wall or the right ventricular outflow tract. In patients with endocardial permanent pacing hemodynamic complications are associated with the development of pacemaker-induced cardiomyopathy due to permanent pacing of the right ventricle apex and tricuspid regurgitation. Complications such as bacterial endocarditis, infection of the pacemaker and its bed, hemopericardium, subclavian vein occlusion, pericarditis, peacemaker dislocation and lead fracture were less common. Two cases of cardiac strangulation were detected.Conclusion. Neither epicardial nor endocardial pacemaker implantation guarantee the absence of complications. Implantation of the electrode on the apex of the left ventricle (epicardial pacemaker system), in the area of the His bundle (endocardial pacemaker system), prevents the development of hemodynamic complications. The most rational is the use of a primary epicardial pacemaker system. Such approach allows the veins to be preserved for endocardial stimulation at an older age.

Background. Currently pacing is the only treatment option for life-threatening bradyarrhythmias. Considering the specific factors of pediatric patients, specialists in this field should be highly professional.Aim. To present the experience and retrospective analysis of complications of permanent pacing in children and adolescents from Tomsk National Research Medical Center.Material and Methods. Complications of permanent pacing in children with structurally normal heart and children with congenital heart defects were analyzed. The follow-up was from 1999 to 2021 years. 256 patients aged from 1 month to 18 years participated in the study. Epicardial pacemaker was implanted in 173 children, endocardial – in 83 patients. Average time from primary implantation to complications was 2.1 ± 2.7 years.Results. Hemodynamic complications are the most common among patients with epicardial and endocardial permanent pacing. Hemodynamic complications with epicardial permanent pacing are associated with intraventricular dissynchrony due to stimulation in the area of the lateral wall or the right ventricular outflow tract. In patients with endocardial permanent pacing hemodynamic complications are associated with the development of pacemaker-induced cardiomyopathy due to permanent pacing of the right ventricle apex and tricuspid regurgitation. Complications such as bacterial endocarditis, infection of the pacemaker and its bed, hemopericardium, subclavian vein occlusion, pericarditis, peacemaker dislocation and lead fracture were less common. Two cases of cardiac strangulation were detected.Conclusion. Neither epicardial nor endocardial pacemaker implantation guarantee the absence of complications. Implantation of the electrode on the apex of the left ventricle (epicardial pacemaker system), in the area of the His bundle (endocardial pacemaker system), prevents the development of hemodynamic complications. The most rational is the use of a primary epicardial pacemaker system. Such approach allows the veins to be preserved for endocardial stimulation at an older age.