Limited Relationship Between Echocardiographic Measures and Electrocardiographic Markers of Left Ventricular Size in Healthy Children.

Pediatric ECG standards have been defined without echocardiographic confirmation of normal anatomy. The Pediatric Heart Network Normal Echocardiogram Z-score Project provides a racially diverse group of healthy children with normal echocardiograms. We hypothesized that ECG and echocardiographic measures of left ventricular (LV) dimensions are sufficiently correlated in healthy children to imply a clinically meaningful relationship. This was a secondary analysis of a previously described cohort including 2170 digital ECGs. The relationship between 6 ECG measures associated with LV size were analyzed with LV Mass (LVMass-z) and left ventricular end-diastolic volume (LVEDV-z) along with 11 additional parameters. Pearson or Spearman correlations were calculated for the 78 ECG-echocardiographic pairs with regression analyses assessing the variance in ECG measures explained by variation in LV dimensions and demographic variables. ECG/echocardiographic measurement correlations were significant and concordant in 41/78 (53%), though many were significant and discordant (13/78). Of the 6 ECG parameters, 5 correlated in the clinically predicted direction for LV Mass-z and LVEDV-z. Even when statistically significant, correlations were weak (0.05-0.24). R2 was higher for demographic variables than for echocardiographic measures or body surface area in all pairs, but remained weak (R2 ≤ 0.17). In a large cohort of healthy children, there was a positive association between echocardiographic measures of LV size and ECG measures of LVH. These correlations were weak and dependent on factors other than echocardiographic or patient derived variables. Thus, our data support deemphasizing the use of solitary, traditional measurement-based ECG markers traditionally thought to be characteristic of LVH as standalone indications for further cardiac evaluation of LVH in children and adolescents.

Impact of a paediatric cardiac rehabilitation programme upon patient quality of life.

INTRODUCTION: Cardiac rehabilitation programmes for paediatric patients with congenital heart disease (CHD) have been shown to promote emotional and physical health without any associated adverse events. While prior studies have demonstrated the effectiveness of these types of interventions, there has been limited research into how the inclusion of psychological interventions as part of the programme impacts parent-reported and patient-reported quality of life. MATERIALS AND METHODS: Patients between the ages of 7 and 24 years with CHD completed a cardiac rehabilitation programme that followed a flexible structure of four in person-visits with various multidisciplinary team members, including paediatric psychologists. Changes in scores from the earliest to the latest session were assessed regarding exercise capacity, patient functioning (social, emotional, school, psychosocial), patient general and cardiac-related quality of life, patient self-concept, and patient behavioural/emotional problems. RESULTS: From their baseline to final session, patients exhibited significant improvement in exercise capacity (p = 0.00009). Parents reported improvement in the patient's emotional functioning, social functioning, school functioning, psychosocial functioning, cognitive functioning, communication, and overall quality of life. While patients did not report improvement in these above areas, they did report perceived improvement in certain aspects of cardiac-related quality of life and self-concept. DISCUSSION: This paediatric cardiac rehabilitation programme, which included regular consultations with paediatric psychologists, was associated with divergent perceptions by parents and patients on improvement related to quality of life and other aspects of functioning despite improvement in exercise capacity. Further investigation is recommended to identify underlying factors associated with the differing perceptions of parents and patients.

Methadone's Effect on Cardiac Repolarization: Safety in the PICU.

OBJECTIVES: Opioids are routinely used in the PICU. Methadone is an effective method of preventing and treating iatrogenic opioid withdrawal; however, it carries an Food and Drug Administration Boxed Warning due to the potential to prolong the corrected QT interval and potentially lead to life-threatening arrhythmias. Guidelines on the safe use of methadone have limited applicability to children since their cardiac intervals differ from those of adults. There is little data on the electrophysiologic effects in the pediatric population. We set out to describe the safety of methadone use in the PICU, hypothesizing that methadone does not cause a significant change in corrected QT interval from baseline. DESIGN: Retrospective cohort study. SETTING: Children's Hospital of Wisconsin, Milwaukee, WI. PATIENTS: Fifty-one patients, age less than or equal to 18 years old, initiated on methadone during PICU admission, over an 11-month period, for the prevention or treatment of opioid withdrawal. INTERVENTIONS: Retrospective data queried from the electronic health record and stored telemetry waveforms obtained from an automated real-time patient data acquisition software system (BedMasterEx; Anandic Medical Systems AG, Feuerthalen, Switzerland). MEASUREMENTS AND MAIN RESULTS: Corrected QT intervals were not significantly different at 12 hours, 96 hours, or PICU discharge (p values: 0.57, 0.54, and 0.34) when compared to baseline. The median change in corrected QT from baseline to 12 hours after the first dose of methadone was 5 ms (interquartile range, -12 to 11 ms), 0 ms to steady state (interquartile range, -18 to 18 ms), and 5 ms from baseline to 12 hours after the highest dose of methadone (interquartile range, -14 to 16 ms). The most common primary diagnosis was structural heart disease (29% of subjects) in our cohort and every subject that experienced an increase in corrected QT interval greater than or equal to 40 ms had some form of structural heart disease. CONCLUSIONS: Methadone did not significantly prolong the corrected QT interval in a population of critically ill children, suggesting that it can be safely used in this population, although patients with structural heart disease may warrant closer monitoring.

Cardiac Magnetic Resonance Imaging (MRI) in Children is Safe with Most Pacemaker Systems, Including Those with Epicardial Leads.

Magnetic resonance imaging (MRI) of patients with pacemakers remains concerning because of possible magnetic field effects on the device. Many pacemaker models are labeled as non-conditional, or contraindicated for MRI, or do not have any specific safety guidelines listed. This study describes our experience with pacemaker function and adverse events in pediatric and young adult patients after clinically indicated MRI scanning at 1.5 Tesla (T). We hypothesized that generator battery voltage, pacemaker lead threshold, and lead impedance would not be altered by MRI. This was a retrospective review of Children's Wisconsin clinical MRI data for all patients with pacemakers scanned between January 1, 2010 and March 31, 2018. Pacemakers were interrogated by the Electrophysiology Team before and immediately after MRI and at outpatient follow up. Twenty-one patients underwent forty-four MRI scans. No significant immediate changes were seen in any pacemaker parameter for any manufacturer/model/lead at the time of MRI. At first clinical follow up post MRI, (median 4.4 months, range 0.2-12.3), battery voltage was reduced (2.78 V pre-MRI versus 2.77 V at follow up, p = 0.02), but there were no other significant changes. No adverse events were noted. Pediatric patients with pacemakers, including those with epicardial leads, can be scanned at 1.5 T safely without alteration in pacemaker function. Using appropriate precautions, pediatric patients with pacemakers can be imaged with MRI.

Outcomes of catheter ablation of anteroseptal and midseptal accessory pathways in pediatric patients.

BACKGROUND: Outcomes for catheter ablation of accessory pathways in pediatric patients have steadily improved, with the exception of pathways located in the anteroseptal (AS) and midseptal (MS) regions, where success is limited by the close proximity of normal atrioventricular conduction. OBJECTIVE: The purpose of this study was to evaluate the efficacy of different catheter approaches and ablation energy modalities used for catheter ablation at these sites. METHODS: A retrospective review was performed of all electrophysiology studies conducted between July 2001 and July 2017. Acute success and recurrence rates were assessed by comparing catheter approaches and energy modalities used for ablation. RESULTS: A total of 255 electrophysiology procedures were performed in 223 patients (178 AS, 72 MS, 5 unspecified). Ablation was attempted in 241 procedures, with acute success in 87% (AS 89%, MS 83%). Recurrence was evident in 18% of successful ablation procedures (AS 18%, MS 19%). Success rates were higher with repeat procedures than with primary procedures (P = .006). Multiple approaches were more often used for AS pathways, though no single approach was superior. There was no difference in success when comparing energy modalities, though the overall recurrence rate was higher for cryoablation. Significant complications occurred in 1.2% of procedures, though no patient had complete heart block. CONCLUSION: Ablation of AS and MS pathways remains challenging. Multiple approaches are often necessary to successfully ablate AS pathways. While both ablation energy modalities were equally successful, cryoablation may be associated with a higher chance of recurrence. Recurrences and repeat procedures may be anticipated to minimize risk to normal atrioventricular conduction during ablation in these regions.

Cardiac arrest in a healthy child due to paradoxical embolus across a previously unrecognised sinus venosus defect.

A previously healthy, preadolescent female suffered an unwitnessed cardiac arrest with prompt return of circulation following bystander initiated resuscitation. Workup demonstrated the cause of her cardiac arrest to be distal left anterior descending coronary artery occlusion with small apical left ventricular transmural myocardial infarction, from a paradoxical embolus traversing a previously undiagnosed large sinus venous defect. This case demonstrates the value of cardiac magnetic resonance imaging may bring to the diagnosis of the pathophysiology leading to cardiac arrest.

Chronotropic incompetence in paediatric heart transplant recipients with prior congenital heart disease.

BACKGROUND: Cardiopulmonary exercise testing has been used to measure functional capacity in children who have undergone a heart transplant. Cardiopulmonary exercise testing results have not been compared between children transplanted for a primary diagnosis of CHD and those with a primary diagnosis of cardiomyopathy despite differences in outcomes. This study is aimed to compare cardiopulmonary exercise testing performance between these two groups. METHODS: Patients who underwent heart transplant with subsequent cardiopulmonary exercise testing at least 6 months after transplant at our institution were identified. They were then divided into two groups based on primary cardiac diagnosis: CHD or cardiomyopathy. Patient characteristics, echocardiograms, cardiac catheterisations, outcomes, and cardiopulmonary exercise test results were compared between the two groups. RESULTS: From the total of 35 patients, 15 (43%) had CHD and 20 (57%) had cardiomyopathy. Age at transplant, kidney disease, lung disease, previous rejection, coronary vasculopathy, catheterisation, and echocardiographic data were similar between the groups. Mean time from transplant to cardiopulmonary exercise testing, exercise duration, and maximum oxygen consumption were similar in both groups. There was a difference in heart rate response with CHD heart rate response of 63 beats per minute compared to cardiomyopathy group of 78 (p = 0.028). Patients with CHD had more chronotropic incompetence than those with cardiomyopathy (p = 0.036). CONCLUSION: Primary diagnosis of CHD is associated with abnormal heart rate response and more chronotropic incompetence compared to those transplanted for cardiomyopathy.

Electrocardiograms in Healthy North American Children in the Digital Age.

BACKGROUND: Interpretation of pediatric ECGs is limited by lack of accurate sex- and race-specific normal reference values obtained with modern technology for all ages. We sought to obtain contemporary digital ECG measurements in healthy children from North America, to evaluate the effects of sex and race, and to compare our results to commonly used published datasets. METHODS: Digital ECGs (12-lead) were retrospectively collected for children ≤18 years old with normal echocardiograms at 19 centers in the Pediatric Heart Network. Patients were classified into 36 groups: 6 age, 2 sex, and 3 race (white, black, and other/mixed) categories. Standard intervals and amplitudes were measured; mean±SD and 2nd/98th percentiles were determined by age group, sex, and race. For each parameter, multivariable analysis, stratified by age, was conducted using sex and race as predictors. Parameters were compared with 2 large pediatric ECG data sets. RESULTS: Among ECGs from 2400 children, significant differences were found by sex and race categories. The corrected QT interval in lead II was greater for girls compared with boys for age groups ≥3 years (P≤0.03) and for whites compared with blacks for age groups ≥12 years (P<0.05). The R wave amplitude in V6 was greater for boys compared with girls for age groups ≥12 years (P<0.001), for blacks compared with white or other race categories for age groups ≥3 years (P≤0.006), and greater compared with a commonly used public data set for age groups ≥12 years (P<0.0001). CONCLUSIONS: In this large, diverse cohort of healthy children, most ECG intervals and amplitudes varied by sex and race. These differences have important implications for interpreting pediatric ECGs in the modern era when used for diagnosis or screening, including thresholds for left ventricular hypertrophy.

Transplacental treatment of fetal tachycardia: A systematic review and meta-analysis.

OBJECTIVE: Multiple transplacental medications can be used to treat fetal tachycardia. We sought to perform a systematic review and meta-analysis to determine whether digoxin, flecainide, or sotalol was the most efficacious therapy for converting fetal tachycardia to sinus rhythm. METHOD: We performed a systematic review and meta-analysis to compare digoxin, flecainide, or sotalol as first-line therapy for fetal tachycardia. Studies were identified by a search of PubMed (Medline), Web of Science, and Scopus. RESULTS: There were 21 studies included. Flecainide (OR: 1.4, 95% CI: 1.1-2.0, I2  = 60%, P = 0.03) and sotalol (OR:1.4, 95% CI:1.1-2.0, I2  = 30%, P = 0.02) were superior to digoxin for conversion of fetal tachycardia to sinus rhythm. In those with hydrops, the benefit over digoxin was more notable for both flecainide (OR: 5.0, 95% CI: 2.5-10.0, I2  = 0%, P < 0.001) and sotalol (OR: 2.5, 95% CI: 1.7-5.0, I2  = 0%, P < 0.001). When limited to atrioventricular reentrant tachycardia, flecainide was superior to digoxin (OR:1.7, 95% CI:1.1-3.3, I2  = 62%, P = 0.03) and sotalol (OR:1.3, 95% CI:1.1-1.7, I2  = 0%, P = 0.01). CONCLUSION: Digoxin should not be first-line therapy for fetal tachycardia, particularly in the presence of hydrops fetalis. Flecainide should be the first-line therapy of choice in atrioventricular reentrant tachycardia. Further study may identify further sub-populations responding differently.

Chronic Arrhythmias in the Setting of Heterotaxy: Differences between Right and Left Isomerism.

So-called heterotaxy affects lateralization of the thoracic and abdominal organs. Congenital malformations may be present in one of several organ systems. Cardiac involvement includes both structural and conduction abnormalities. Data regarding arrhythmias in heterotaxy come from case reports and small case series. We pooled available data to further characterize arrhythmias in heterotaxy. A systematic review of the literature for manuscripts describing arrhythmias in heterotaxy patients was conducted. Databases including PubMed, EMBASE, and Ovid were searched. Studies describing arrhythmias in patients with heterotaxy were included if they were in English and presented characteristics of the arrhythmias. Arrhythmia characteristics were abstracted and are presented as pooled data. Freedom from arrhythmia by age was then analyzed using Kaplan-Meier analysis. A total of 19 studies with 121 patients were included in the pooled analysis. Those with right isomerism were found to be more likely to have atrial flutter, atrial tachycardia, junctional tachycardia, and ventricular tachycardia. Those with left isomerism were more likely to have atrioventricular block, intraventricular conduction delay, sick sinus syndrome, and atrioventricular nodal reentry tachycardia. Median age of onset for all arrhythmias was 4 years with no difference by specific arrhythmia or isomerism. Those with right and left isomerism are at risk for different arrhythmias but are likely to develop arrhythmias at the same age. Those with left isomerism are more likely to require pacemaker placement due to atrioventricular block. Understanding these differences allows for focused surveillance of development of these arrhythmias.

Comparison of risk factors and outcomes for pediatric patients listed for heart transplantation after bidirectional Glenn and after Fontan: an analysis from the Pediatric Heart Transplant Study.

BACKGROUND: Patients listed for transplant after the bidirectional Glenn (BDG) may have better outcomes than patients listed after Fontan. This study examined and compared outcomes after listing for BDG and Fontan patients. METHODS: All patients listed for transplant after the BDG in the Pediatric Heart Transplant Study between January 1993 and December 2008 were evaluated. Comparisons were made with Fontan patients and with a matched cohort of congenital heart disease patients. Competing outcomes analysis and actuarial survival were evaluated for the study populations, including an examination of various risk factors. RESULTS: Competing outcomes analysis for BDG and Fontan patients after listing were similar. There was no difference in actuarial survival after listing or transplant among the 3 cohorts. Mechanical ventilation, United Network of Organ Sharing status, and age were risk factors for death after listing in BDG and Fontan patients, but ventilation at the time of transplant was significant only for the Fontan patients. Mortality was increased in Fontan patients listed < 6 months after surgery compared with patients listed > 6 months after surgery, but no difference was observed in BDG patients. There was a trend toward improved survival after listing for both populations across 3 eras of the study, but this did not reach statistical significance. CONCLUSION: Outcomes after listing for BDG and Fontan patients are similar. Mechanical ventilation at the time of transplant remains a significant risk factor for death in the Fontan population, as does listing for transplant soon after the Fontan, suggesting that some patients may benefit from transplant instead of Fontan completion.