title: Right ventricular endomyocardial biopsy in children and adolescents with drug-refractory arrhythmia.
abstract: Purpose This study aimed to assess the results of endomyocardial biopsy from the right ventricle to establish the possible cause for drug-refractory arrhythmias in children. Materials and methods We enrolled 19 consecutive young patients with drug-refractory arrhythmia, from 2010 to 2013, who underwent endomyocardial biopsy. Inclusion criteria were as follows: age <18 years with a structurally normal heart or mild changes in a structure of the heart initially diagnosed as arrhythmia-induced cardiomyopathy. Overall, 86 biopsies were performed in 19 patients. Histopathological analysis, immunohistochemistry, and polymerase chain reaction were used for the interpretation of the endomyocardial biopsy.
  
  
  RESULTS
  The mean age of the patient population was 14.1±2.9 year (range from 7 to 17 years). All these patients had a history of drug-refractory arrhythmia for >5 months (mean 30 months). Patients underwent a complete history investigation, physical examination, laboratory studies, echocardiography, electrocardiography, treadmill test, and Holter monitoring before endomyocardial biopsy; two patients with arrhythmogenic right ventricular dysplasia had implantable cardioverter defibrillator implantation and further appropriate successful device shocks. Myocarditis was diagnosed based on histopathological and immunohistological analyses in nine (47.4%) patients. Polymerase chain reaction was positive for viral genome in four of them; five patients had active myocarditis. Radiofrequency ablation was performed in 17 patients; five out of six (83%) endomyocardial biopsy-proved myocarditis patients had successful radiofrequency ablation. No significant complication was reported during ablation and endomyocardial biopsy.
  
  
  CONCLUSIONS
  Approximately half of the children with drug-refractory arrhythmia had unsuspected myocarditis according to the results of the endomyocardial biopsy.
authors.affiliation: 1Cardiology Department,Almazov Federal Medical Research Center;St. Petersburg,Russia.
authors.forename: Elena
authors.initials: E
authors.lastname: Vasichkina
authors.affiliation: 2Cardiology Department,Astghik Medical Center,Yerevan,Armenia.
authors.forename: Hermine
authors.initials: H
authors.lastname: Poghosyan
authors.affiliation: 1Cardiology Department,Almazov Federal Medical Research Center;St. Petersburg,Russia.
authors.forename: Lubov
authors.initials: L
authors.lastname: Mitrofanova
authors.affiliation: 1Cardiology Department,Almazov Federal Medical Research Center;St. Petersburg,Russia.
authors.forename: Roman
authors.initials: R
authors.lastname: Tatarsky
authors.affiliation: 1Cardiology Department,Almazov Federal Medical Research Center;St. Petersburg,Russia.
authors.forename: Dmitry
authors.initials: D
authors.lastname: Lebedev
mesh_terms: D000293:Adolescent; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D001145:Arrhythmias, Cardiac / Q000175:diagnosis* / Q000188:drug therapy / Q000209:etiology; D001706:Biopsy / Q000379:methods*; D002648:Child; D004351:Drug Resistance; D005260:Female; D005500:Follow-Up Studies; D006352:Heart Ventricles / Q000473:pathology*; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D009205:Myocarditis / Q000150:complications* / Q000175:diagnosis; D009206:Myocardium / Q000473:pathology*; D011446:Prospective Studies; D015203:Reproducibility of Results
chemical_list: D000889:Anti-Arrhythmia Agents
keywords: Endomyocardial biopsy; children and adolescents; drug-refractory arrhythmia; myocarditis