Prevalence of early repolarisation pattern in children

Heart rate variability in children and adolescents with incidentally found early repolarization pattern

BACKGROUND

Early repolarization pattern (ERP) on electrocardiogram (ECG) was long considered benign, but recent data suggest a potential association with fatal arrhythmia and sudden cardiac death. Its relevance in pediatric populations remains unclear. This study investigated the risk of premature death and arrhythmia in children with incidentally found early repolarization using ECG and heart rate variability parameters.

METHODS

This cross-sectional study included healthy children aged 6-18 years with incidentally detected ERP (study group) and age- and sex-matched controls without ERP. All participants underwent medical history evaluation, physical examination, 12-lead ECG, transthoracic echocardiography, and 24-h Holter monitoring. ECG parameters (P wave, QTc, JT, Tp-e, and their dispersions), time-domain (SDNN, SDANN, SDNN-i, r-MSSD, pNN50), and frequency-domain (HF, LF, LF/HF) HRV parameters were analyzed.-i, r-MSSD, pNN50 and "Frequency-domain" parameters HF, LF, LF/HF were obtained.

RESULTS

The study group had lower heart rates (p = 0.020) and increased JT dispersion (p = 0.025). Interventricular septal thickness was significantly greater in the ERP group (p = 0.030). LF/HF ratio (p = 0.045), awake HF (p = 0.046), and awake LF/HF (p = 0.036) were significantly higher in ERP patients. Parasympathetic activity predominance was more evident in males. ERP localized in inferolateral leads was associated with higher heart rate and lower SDNN and VLF during sleep (p = 0.049, p = 0.040, p = 0.040, respectively).

CONCLUSION

Incidental ERP in children was not associated with arrhythmic events but correlated with increased parasympathetic tone. Inferolateral ERP may indicate a relatively higher autonomic imbalance risk.

ATP1A3-Encoded Sodium-Potassium ATPase Subunit Alpha 3 D801N Variant Is Associated With Shortened QT Interval and Predisposition to Ventricular Fibrillation Preceded by Bradycardia

Background

Pathogenic variation in the ATP1A3‐encoded sodium‐potassium ATPase, ATP1A3, is responsible for alternating hemiplegia of childhood (AHC). Although these patients experience a high rate of sudden unexpected death in epilepsy, the pathophysiologic basis for this risk remains unknown. The objective was to determine the role of ATP1A3 genetic variants on cardiac outcomes as determined by QT and corrected QT (QTc) measurements.

Methods and Results

We analyzed 12‐lead ECG recordings from 62 patients (male subjects=31, female subjects=31) referred for AHC evaluation. Patients were grouped according to AHC presentation (typical versus atypical), ATP1A3 variant status (positive versus negative), and ATP1A3 variant (D801N versus other variants). Manual remeasurements of QT intervals and QTc calculations were performed by 2 pediatric electrophysiologists. QTc measurements were significantly shorter in patients with positive ATP1A3 variant status (P<0.001) than in patients with genotype‐negative status, and significantly shorter in patients with the ATP1A3‐D801N variant than patients with other variants (P<0.001). The mean QTc for ATP1A3‐D801N was 344.9 milliseconds, which varied little with age, and remained <370 milliseconds throughout adulthood. ATP1A3 genotype status was significantly associated with shortened QTc by multivariant regression analysis. Two patients with the ATP1A3‐D801N variant experienced ventricular fibrillation, resulting in death in 1 patient. Rare variants in ATP1A3 were identified in a large cohort of genotype‐negative patients referred for arrhythmia and sudden unexplained death.

Conclusions

Patients with AHC who carry the ATP1A3‐D801N variant have significantly shorter QTc intervals and an increased likelihood of experiencing bradycardia associated with life‐threatening arrhythmias. ATP1A3 variants may represent an independent cause of sudden unexplained death. Patients with AHC should be evaluated to identify risk of sudden death.

Incidental electrocardiogram abnormalities in children undergoing polysomnography

STUDY OBJECTIVES

Monitoring electrocardiogram (ECG) is an integral component of pediatric polysomnography (PSG). There is limited data regarding arrhythmia and conduction disturbances in the pediatric population undergoing a PSG. In this work we present abnormal ECG findings during PSG in our sleep center.

METHODS

A retrospective chart review from children who underwent PSG read by a single Sleep Medicine physician in the last year was carried out. Findings in children without cardiac disease and with first or second degree atrioventricular block (AVB) were compared to those from children with premature ventricular contractions (PVC).

RESULTS

A total of 1,235 PSGs were included. Twenty-four children (9 girls and 15 boys) aged 2-17 years (median 9 years) were identified with arrhythmias or conduction disturbances (1.9%). Nineteen out of 24 of these children (79.2%) had obstructive apnea-hypopnea index (oAHI) > 1 event/h; this frequency was not significantly different from that found in the whole group of 1,235 children. No statistically significant difference was found between children with AVB or PVC. Seven out of nine children with AVB and seven out of 10 with PVC had oAHI > 1 event/h, while eight children with AVB out of nine and four out of 10 with PVC were males (Fisher exact test p=0.04). None of the children were found to have a structural or conduction abnormality when referred to cardiology.

CONCLUSIONS

Our study supports that ECG abnormalities are rare in PSGs of children and not associated with cardiac disease or sleep disorders but appear more commonly in males.

Clinical significance of inferolateral early repolarisation and late potentials in children with Brugada Syndrome

INTRODUCTION

The clinical utility of inferolateral early repolarisation (ER) and late potentials (LP) in children with Brugada Syndrome (BrS) has not been previously evaluated. The aim of this study was to determine the prevalence of electrocardiographic (ECG) abnormalities in children with BrS, and to investigate their relationship with clinical outcomes.

METHODS

43 patients with BrS and 47 controls aged ≤18 undergoing systematic clinical and ECG evaluation, including signal-averaged ECG (SAECG) and pharmacological provocation testing, between 2003 and 2019 were included.

RESULTS

Four patients with BrS (9%) presented with a spontaneous type 1 Brugada pattern; the remaining 39 (91%) were diagnosed following ajmaline provocation testing. Twelve BrS patients (28%) had late potentials (LP) on SAECG compared to 1 (2%) in controls (p = 0.001). LP were more common in 5 patients with a high-risk phenotype (60% vs 24%) but this was not statistically significant. Twelve patients with BrS (28%) had inferolateral early repolarisation (ER) and 2 (5%) had fractionated QRS (f-QRS), but there were no statistically-significant differences with controls in these parameters. A significant arrhythmia (non-sustained ventricular tachycardia or atrial fibrillation) was seen in 4 patients (9%).

CONCLUSIONS

This study shows a high prevalence of SAECG abnormalities in children with BrS compared with controls, but this was not significantly associated with a high-risk phenotype.