Reliability of Left Ventricular Hypertrophy by ECG Criteria in Children with Syncope: Do the Criteria Need to be Revised?

In the outpatient setting, children who present with syncope routinely undergo electrocardiograms (ECG). Because of concerns for hypertrophic cardiomyopathy, children with syncope meeting ECG criteria for left ventricular hypertrophy (LVH) will frequently undergo an echocardiogram. Our objectives were to determine whether Davignon criteria for ECG waves overestimate LVH in children presenting with syncope, and to study the usefulness of echocardiography in these children. We hypothesize that the Davignon criteria presently used for interpretation of ECGs overestimate LVH, resulting in unnecessary echocardiography in this clinical setting. The clinical database of The Children's Hospital of Philadelphia was evaluated from 2002 to 2012 to identify children between 9 and 16 years of age, who presented with non-exercise-induced, isolated syncope. From this group of patients, only those with clear-cut evidence of LVH (by Davignon criteria), who also underwent an echocardiogram, were selected. A total of 136 children with syncope were identified as having LVH by Davignon ECG criteria. None of these patients manifested any evidence of hypertrophic cardiomyopathy, with normal ventricular septum (average Z-score -0.68 ± 0.84), LV posterior wall (average Z-score -0.66 ± 1.18) and LV mass (average Z-score 0.52 ± 1.29). No significant correlation was found between summed RV6 plus SV1 and LV mass. Correlations between additional ECG parameters and measures of LVH by echocardiography were similarly poor. In children presenting with syncope and LVH by ECG, there was no evidence of true LVH by echocardiography. We propose that the Davignon ECG criteria for interpreting LVH in children overestimate the degree of hypertrophy in these children and the yield of echocardiography is extremely low.

Transcatheter Leadless Pacing in Children: A PACES Collaborative Study in the Real-World Setting.

BACKGROUND: Transcatheter Leadless Pacemakers (TLP) are a safe and effective option for adults with pacing indications. These devices may be an alternative in pediatric patients and patients with congenital heart disease for whom repeated sternotomies, thoracotomies, or transvenous systems are unfavorable. However, exemption of children from clinical trials has created uncertainty over the indications, efficacy, and safety of TLP in the pediatric population. The objectives of this study are to evaluate clinical indications, procedural characteristics, electrical performance, and outcomes of TLP implantation in children. METHODS: Retrospective data were collected from patients enrolled in the Pediatric and Congenital Electrophysiology Society TLP registry involving 15 centers. Patients ≤21 years of age who underwent Micra (Medtronic Inc, Minneapolis, MN) TLP implantation and had follow-up of ≥1 week were included in the study. RESULTS: The device was successfully implanted in 62 of 63 registry patients (98%) at a mean age of 15±4.1 years and included 20 (32%) patients with congenital heart disease. The mean body weight at TLP implantation was 55±19 kg and included 8 patients ≤8 years of age and ≤30 kg in weight. TLP was implanted by femoral (n=55, 87%) and internal jugular (n=8, 12.6%) venous approaches. During a mean follow-up period of 9.5±5.3 months, there were 10 (16%) complications including one cardiac perforation/pericardial effusion, one nonocclusive femoral venous thrombus, and one retrieval and replacement of TLP due to high thresholds. There were no deaths, TLP infections, or device embolizations. Electrical parameters, including capture thresholds, R wave sensing, and pacing impedances, remained stable. CONCLUSIONS: Initial results from the Pediatric and Congenital Electrophysiology Society TLP registry demonstrated a high level of successful Micra device implants via femoral and internal venous jugular approaches with stable electrical parameters and infrequent major complications. Long-term prospective data are needed to confirm the reproducibility of these initial findings.

Incidence of life-threatening events in children with Wolff-Parkinson-White syndrome: Analysis of a large claims database.

BACKGROUND: Previous estimates of life-threatening event (LTE) risk in Wolff-Parkinson-White (WPW) syndrome are limited by selection bias inherent to tertiary care referral-based cohorts. OBJECTIVE: This analysis sought to measure LTE incidence in children with WPW syndrome in a large contemporary representative population. METHODS: A retrospective cohort study was conducted using claims data from the IBM MarketScan Research Databases, evaluating subjects with WPW syndrome (age 1-18 years) from any encounter between January 1, 2013, and December 31, 2018. Subjects with congenital heart disease and cardiomyopathy were excluded. The primary outcome was diagnosis of ventricular fibrillation (VF); a composite outcome, LTE, was defined as occurrence of VF and/or cardiac arrest. VF and LTE rates were compared to matched representative controls without WPW syndrome (3:1 ratio). RESULTS: The prevalence of WPW syndrome was 0.03% (8733/26,684,581) over a median follow-up of 1.6 years (interquartile range 0.7-2.9 years). Excluding congenital heart disease/cardiomyopathy, 6946 subjects were analyzed. An LTE occurred in 49 subjects (0.7%), including VF in 20 (0.3%). The incidence of VF was 0.8 events per 1000 person-years, and the incidence of LTE was 1.9 events per 1000 person-years. There were no occurrences of VF in controls; the rate of LTE was 70 times higher in subjects with WPW syndrome (0.7%; 95% confidence interval 0.5%-0.9%) than in controls (0.01%; 95% confidence interval 0%-0.02%). CONCLUSION: The use of a large claims data set allowed for an evaluation of VF and LTE risk in an unselected pediatric population with WPW syndrome. The observed range of 0.8-1.9 events per 1000 person-years is consistent with prior reports from selected populations. A comparison of event rates to matched controls confirms and quantifies the significant elevation in VF and LTE risk in pediatric WPW syndrome.

Drug therapy considerations in arrhythmias in children.

The understanding of the mechanisms of action and side effects of different antiarrhythmic drugs (AAD) are essential for their appropriate use. With the advent of effective and safe ablation therapy, AAD therapy has undergone dramatic changes. This review attempts to understand the rationale behind the clinical use of medical management of different arrhythmias.

Ventricular dysfunction: tachycardia induced cardiomyopathy.

Tachycardia induced cardiomyopathy (TIC) is defined as atrial or ventricular dysfunction as a result of prolonged elevated heart rate that is reversible upon control of the arrhythmia. There may be no underlying structural heart disease primarily responsible for the cardiac dysfunction. We present some examples of arrhythmias causing TIC and the resolution of the ventricular dysfunction following their appropriate management. Included in the review are also the pathophysiology, clinical spectrum, diagnosis and appropriate management of the condition.