ELECTRICAL ACTIVITY OF THE ATRIALS IN CHILDREN WITH PREMATURE VENTRICULAR EXCITATION

Abstract

Introduction: Premature ventricular excitation (PVE) in children is accompanied by a high risk of developing tachyarrhythmic attacks, including supraventricular tachycardia, atrial fibrillation and fibrillation, which poses a threat to the patient's life. Early diagnosis and monitoring of such children are of particular importance in the clinical practice of a pediatric electrocardiologist. Objective: To study the electrical activity of the atria and its relationship with ventricular depolarization, as well as to identify pathological changes in the atria (hyperfunction, hypertrophy) in various types and variants of PVE in children. Materials and methods: The cross-sectional study included 1733 children aged 7–14 years (827 girls, 906 boys) selected from the general school population by simple randomization. The examination program included a questionnaire (interview of children and parents), objective examination, blood pressure and pulse measurement, anthropometry, puberty assessment, 12-channel electrocardiography with subsequent planimetric analysis of the P wave. Results: In healthy children, the amplitude of the P wave in lead II decreased with age (0.65±0.029 mm at 7–10 years and 0.54±0.02 mm at 11–14 years, p<0.001), and the duration increased (0.065±0.001 s to 0.081±0.002 s, p<0.001). In patients with various manifestations of PVG, differences in the amplitude and duration of the P and R waves, the ratio of their values ​​in the WPW, Mahaim and CLC phenomena were noted, which indicates depolarization disorders and possible atrial hyperfunction. The Macruz index showed unreliability in the diagnosis of atrial hypertrophy in most forms of PVG due to the shortened P-Q segment and the risk of false-positive results. Discussion: Planimetric analysis of P wave vectors and areas revealed regional features of atrial electrophysiology in children of this region that differ from literary standards, which is important to consider when interpreting ECG. A delay in biological inversion of the right atrium and hyperfunction of the left atrium in patients with PVG due to hemodynamic overload were noted. Conclusions: Comprehensive analysis of atrial electrical activity, including interval, vector and planimetric parameters of the P wave, provides valuable information for diagnosis, risk stratification and prognosis in children with PVD in the clinical practice of pediatric electrocardiologists.