<p>This study presents literature data over the past few years on markers of acute myocardial damage after radiofrequency ablation. Information on markers such as troponin I and T, creatine phosphokinase and its fractions, CRP and interleukins and myoglobin is presented in detail. For each potential myocardial damage indicator, data related to their expression site, chemical basis of each marker and correlation between the degree of damage caused by radiofrequency exposure and the levels of various biomarkers of myocardial damage are provided.</p><p>Received 12 November 2019. Revised 26 February 2020. Accepted 27 February 2020.</p><p><strong>Funding:</strong> The study did not have sponsorship.</p><p><strong>Conflict of interest</strong>: Authors declare no conflict of interest.</p><p><strong>Author contributions</strong><br />Conception and study design: O.L. Zajfrid, R.B. Tatarsky, E.S. Vasichkina<br />Drafting the article: O.L. Zajfrid, K.A. Chueva, A.V. Mikhailov <br />Critical revision of the article: O.L. Zajfrid, R.B. Tatarsky, E.S. Vasichkina, I.L. Nikitina, D.S. Lebedev<br />Final approval of the version to be published: O.L. Zajfrid, K.A. Chueva, E.S. Vasichkina, A.V. Mikhailov, D.S. Lebedev, I.L. Nikitina, R.B. Tatarsky</p>

Aim. To assess the severity of myocardial damage and inflammation after radiofrequency ablation in children and adolescents using biochemical markers.Material and methods. The study included 58 children with tachyarrhythmias (Wolff-Parkinson-White (WPW) syndrome, WPW phenomenon, atrial tachycardia, paroxysmal atrioventricular reciprocating tachycardia, ventricular tachycardia) who underwent catheter ablation from July to October 2019. Before and after surgical treatment (after 2 hours and 5 days), the blood concentrations of myocardial damage and inflammation biomarkers (myoglobin, creatine phosphokinase-MB, interleukin-8, C-reactive protein, tumor necrosis factor alpha, metalloproteinase (MMP)-2, MMP-9, heart-type fatty acid binding protein). During the operation, catheter ablation parameters (power, temperature, application duration), the localization of arrhythmogenic focus and the type of ablation catheter were recorded. Their relationship with changes in the concentration of biochemical markers before and after intervention was studied.Results. Two hours after the operation, the concentrations of myoglobin, creatine phosphokinase-MB, MMP-9, heart-type fatty acid binding protein were increased several times (p<0,05). Changes in concentrations of interleukin-8, tumor necrosis factor alpha after the operation was not revealed. On the 5th day, elevated levels of cardiac markers returned to baseline values. MMP-9 level also decreased, but was higher than the preoperative level. Using Spearman’s correlation analysis, a direct relationship was revealed between the application duration and heart-type fatty acid binding protein level.Conclusion. Radiofrequency ablation is a safe method of treating arrhythmias in children and adolescents, since there is low volume of damaged myocardium. There was a slight increase in the level of biochemical markers after ablation (myoglobin, creatine phosphokinase-MB, fatty acid binding protein, MMP-9), incomparable with their rise in acute coronary syndrome, as well as the rapid decrease in the early postoperative period.

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Atrial fibrillation is the most common persistent arrhythmia in adults; however, it is quite rare in children. In patients without structural heart diseases or extracardiac causes, the genetic basis of the arrhythmia can be assumed. A clinical case of atrial fibrillation in a child, probably associated with the variant D1907H in the SCN10A gene, was described in this article. In spite of a very limited clinical and genetic information on the association of Nav 1.8 channel encoded by SCN10A with atrial arrhythmias, the presented case can further confirm the role of this gene in arrhythmogenesis in children.

The study aims to assess the role of magnetic resonance tomography (MRI) in identifying the substrate of “idiopathic” ventricular arrhythmias in pediatric patients.Methods. One hundred and seven children with “idiopathic” ventricular arrhythmias were enrolled. All patients underwent MRI on a high-field Magnetom Trio A Tim (Siemens) tomograph with a magnetic field induction of 3.0 T.Results. According to MRI data, dilated ventricles and/or a decreased ejection fraction were found in 55 (51%) patients. Based on structural abnormalities of the myocardium patients were divided into 2 groups: group 1 “normal”, without abnormalities, (69 (64.5%) children); group 2 - “fibrosis”, fibrotic changes were detected on late gadolinium enhancement (38 (35.5%) patients). Significant differences of indexed MR-indicators in these two groups were not found. However, in the “fibrosis” group, biventricular dysfunction occurred significantly more often than in the “normal” group, respectively (14 (37%) and 9 (13%) (p = 0.006)).Conclusion. MRI is important in assessing structural changes in pediatric patients with ventricular arrhythmias, and the combination of MRI results with clinical and electrophysiological data can significantly affect the change in management and treatment strategy in pediatric patients.