Age-related blood pressure and electrocardiographic dispersion mapping changes observed in Magadan adolescents

Abstract

Aim. To study age-related electrocardiographic (ECG) dispersion mapping (DM) changes in adolescents with normal blood pressure (BP). ECG-DM makes it possible to assess the severity of myocardial electrophysiological abnormalities, which have not reached clinical manifestations with a standard ECG recording.Material and methods. For the period of 2017-2020, the data of 1140 schoolchildren (590 boys and 550 girls) living in Magadan were analyzed. There were following inclusion criteria: age of 12-17 years, informed consent of parents, health status group 1-2, no prior chronic and acute diseases (vaccinations), and hypertension. Systolic (SBP) and diastolic blood pressure (DBP) were recorded 3 times on the A&D Company Ltd BP monitor (2017, Japan). ECG-DM parameters were obtained using the CardioVisor-06s system (2004, Russia, Moscow): Myocardium index (norm <15%), Rhythm index (norm <20%), right, left atrial (G1-G2) and right, left ventricular depolarization (G3-G4), right and left ventricular repolarization (G5-G6), ventricular depolarization symmetry (G7), intraventricular block (G8), ventricular hypertrophy (G9).Results. In the period from 12 to 17 years old, an age-related increase in BP and a decrease in heart rate were determined (p<0,001). Significant rates of BP increase were observed in girls at the age of 12-13 years (p<0,01), while in boys, yearly differences regard only SBP from 12 years (p<0,05), except for 14-15 years. Sex differences were established at the age of 13 for DBP (p=0,026), from the age of 14 according to SBP, with higher values in boys (p<0,05). From 12 to 17 years old, age-related changes were observed only in the Rhythm index (p<0,001), while the predominance of average normal values was established from the age of 14 in boys (p=0,008) and from 15 years old in girls (p=0,022) relative to younger age. There was also an increase in the proportion of persons with normal values in boys from 28,7 to 50,0%, in girls from 29,4 to 61,7% (p<0,05). The Myocardium index at all ages approached the upper normal limit without dependence on age and sex. According to G1-G9 indicators, normal and borderline values prevailed. The greatest similarity was observed in G1-G2 in 45,6-40,8% of boys and 48,3-46,5% of girls, as well as in G9 — 35,1-39,6% (p>0,05), respectively.The proportion of persons in G5-G6 was lower among boys (6,9 and 7,1%) compared with girls (14,2 and 13,1%) (p=0,002, p=0,010), while other indicators had no significant differences as follows: G3 (9,8 and 7,1%), G4 (4,9 and 4,0%), G7 (5,4 and 6,0%), G8 (1,4 and 1,1%) (p>0,05). Among boys according to G9, age differences were observed at 14-15 years old (p=0,026), while among girls — G1 at 16-17 years old (p=0,035).Conclusion. ECG-DM allows monitoring early cardiac dispersion changes in children aged 12-17 years with a normal blood pressure level and identifying among them those adolescents who need further examination.