Determination of normal ECG persentiles and cardiac conduction disturbances school age children with 12-channel ECG scans

Objective: Electrocardiography (ECG) has been used in the diagnosis of cardiovascular diseases for nearly a hundred years. To identify these diseases, it is necessary to obtain a large number of ECG data to produce the standard values of ECG parameters and to remove the ECG with abnormal findings. Although there are some epidemiological studies in order to determine the frequency of ECG findings related to rhythm and conduction disturbances in healthy children, the information in the current literature on the normal or reference values for pediatric ECGs is limited. Rhythm and conduction disturbances are less common in children than adults. These disturbances may be asymptomatic and may cause significant clinical problems, including sudden death. ECG screening in asymptomatic children is an increasingly accepted approach. The purpose of this study was to determine the normal ECG percentiles in healthy school age children and to determine the prevalence of conduction disorders in our region by determining the frequency of pathologic ECG in these children. Materials and Methods: Our study was a cross-sectional prospective study and 2154 students who received informed consent form from their families in eight randomly selected schools in the city center of Malatya were included in the study. A questionnaire on the children's medical history was distributed to the families of the children. All ECG recordings were evaluated by the same pediatric cardiologists. The records were evaluated in terms of branch block, atrioventricular (AV) block, premature contraction, repolarization disorders and preeksitation syndromes. ECG recordings of all children were evaluated according to age, heart rate, QRS duration, QT, QTc and PR distances, P, QRS, T axes and R / S ratio in leads V1, V2 and V6. 110 children who were thought to have pathology in their ECG were reevaluated in our clinic. Echocardiography (ECHO) was performed in 46 children according to the physical examination and ECG data. 24 hours Holter ECG and exercise test were applied to selected cases. Children were divided into 6-9, 9-13 and 13-18 age groups according to gender and EKGs were investigated. According to these age groups, percentile curves were removed. Statistical analysis was performed with IBM SPSS Statistics version 17.0. Categorical data were identified by number and percent. Numerical data were summarized with median, minimum and maximum values. Results: In this study, a total of 110 (5.1%) of the 2154 children who examined the ECG records in the pre-determined schools were found to have pathology. As a result of evaluation of 2044 children who had no conduction and rhythm disturbance was the mean age 11.4 ± 2.8, and 43.2% (n=895) were male and 56.8% (n=1149) were female. The most common age group was 10 years (n=328) and the median age was 11 years. Echocardiography (ECHO) was performed in all patients who had major pathology (n = 46) in their ECG's. Echocardiographic evaluation revealed that 3 out of 46 children (6.5%) had major cardiac pathology (atrial septal defect: 2, ventricular septal defect: 1) and 8 of the children (17.3%) had minor cardiac pathology (Patent foramen ovale: 5, physiological mitral insufficiency: 2, bicuspid aortic valve: 1) was detected. As a result of the evaluations, it was determined that 35 of the 110 children (31.8%) had palpitation complaints. As a result of ECG evaluation, 18 patients with pathological findings were evaluated and 24 hours Holter ECG was performed. In the ECG and 24-hour Holter ECG evaluation results, 87 (70.9%) of the children had sinusitis arrhythmia, 5 (4.5%) of the children 1.st degree AV block, in 2 (1.8%) rare ventricular extrasystol (VES), in 2 (1.8%) incomplet right branch block, in 1 (0.9%) sinus arrest, in 3 (2.7%) J point elevation 1 (0.9%) ectopic atrial rhythm and in 9 (8.2%) sinus tachycardia were recorded. QTc interval was measured as 0.44-0.46 sec. After the re-drawn ECGs of all 5 cases, QTc interval of 1 (20%) case was measured as 0.46 sec. The ECG of the mothers, fathers and siblings of all cases was also examined. After 24 hours of Holter ECG, exercise test and genetic tests, it was decided to follow one case for long QT syndrome. The heart rate, PR, QT and QTc interval, QRS duration and QTc, P, QRS and T axes along with V, V2 and V6 precordial leads of the R/S ratio children included in the study were also controlled manually after the device calculation. According to age groups were compared these 11 parameters with other studies in the literature. In our study, the average heart rate per minute was higher in all age groups compared to other studies. Therefore, the QT interval was similar compared to other studies, but the mean QTc interval was lower. Similar results were obtained for the PR distance in all age groups with other studies, while QRS duration was shorter. Also, according to age groups, data of 3-10-25-50-75-90 and 97 percentile were obtained. Results: ECG normals can be obtained in school-age children by reaching higher quantities with ECG screening projects similar to our study. In addition, early detection of structural and electrical pathologies that may lead to significant morbidity and sometimes mortality and preventive and therapeutic measures can be taken. The data obtained in this study will guide further studies to determine the frequency of rhythm and conduction disturbances in children. Key words: Electrocardiography, screening, pediatric, percentile