Patterns of Electrocardiographic Abnormalities in Children with Hypertrophic Cardiomyopathy.

Hypertrophic cardiomyopathy (HCM), a common cardiomyopathy in children, is an important cause of morbidity and mortality. Early recognition and appropriate management are important. An electrocardiogram (ECG) is often used as a screening tool in children to detect heart disease. The ECG patterns in children with HCM are not well described.ECGs collected from an international cohort of children, and adolescents (≤ 21 years) with HCM were reviewed. 482 ECGs met inclusion criteria. Age ranged from 1 day to 21 years, median 13 years. Of the 482 ECGs, 57 (12%) were normal. The most common abnormalities noted were left ventricular hypertrophy (LVH) in 108/482 (22%) and biventricular hypertrophy (BVH) in 116/482 (24%) Of the patients with LVH/BVH (n = 224), 135 (60%) also had a strain pattern (LVH in 83, BVH in 52). Isolated strain pattern (in the absence of criteria for hypertrophy) was seen in 43/482 (9%). Isolated pathologic Q waves were seen in 71/482 (15%). Pediatric HCM, 88% have an abnormal ECG. The most common ECG abnormalities were LVH or BVH with or without strain. Strain pattern without hypertrophy and a pathologic Q wave were present in a significant proportion (24%) of patients. Thus, a significant number of children with HCM have ECG abnormalities that are not typical for "hypertrophy". The presence of the ECG abnormalities described above in a child should prompt further examination with an echocardiogram to rule out HCM.

Extra-cardiac and complex Fontan baffle fenestration using radio frequency current via surgical electrocautery.

BACKGROUND: Fontan baffle punctures and creation of Fontan fenestration for cardiac catheterisation procedures remain challenging especially due to the heavy calcification of prosthetic material and complex anatomy. OBJECTIVES: We sought to evaluate our experience using radiofrequency current via surgical electrocautery needle for Fontan baffle puncture to facilitate diagnostic, electrophysiology, and interventional procedures. METHODS: A retrospective chart review of all Fontan patients (pts) who underwent Fontan baffle puncture using radiofrequency energy via surgical electrocautery from three centres were performed from January 2011 to July 2021. RESULTS: A total of 19 pts underwent 22 successful Fontan baffle puncture. The median age and weight were 17 (3-36 years) and 55 (14-88) kg, respectively. The procedural indications for Fontan fenestration creation included: diagnostic study (n = 1), atrial septostomy and stenting (n = 1), electrophysiology study and ablation procedures (n = 8), Fontan baffle stenting for Fontan failure including protein-losing enteropathy (n = 7), and occlusion of veno-venous collaterals (n = 2) for cyanosis. The type of Fontan baffles included: extra-cardiac conduits (n = 12), lateral tunnel (n = 5), classic atrio-pulmonary connection (n = 1), and intra-cardiac baffle (n = 1). A Fontan baffle puncture was initially attempted using traditional method in 6 pts and Baylis radiofrequency trans-septal system in 2 pts unsuccessfully. In all pts, Fontan baffle puncture using radiofrequency energy via electrocautery needle was successful. The radiofrequency energy utilised was (10-50 W) and required 1-5 attempts for 2-5 seconds. There were no vascular or neurological complications. CONCLUSIONS: Radiofrequency current delivery using surgical electrocautery facilitates Fontan baffle puncture in patients with complex and calcified Fontan baffles for diagnostic, interventional, and electrophysiology procedures.

ALARA in Pediatric Electrophysiology Laboratory.

The effects of radiation on patients and the providers are dose-dependent and cumulative. Pediatric patients are not only more sensitive to radiation but also may undergo more procedures and diagnostic tests throughout their lifetime. As providers, the endeavor is to cause no harm and it behooves us to either eliminate or minimize the radiation exposure to patients without affecting the efficacy and outcomes of the diagnostic or therapeutic modalities. Pediatric electrophysiologists have taken the lead in attempting to minimize the radiation exposure to patients and staff with innovative and advanced techniques. The techniques range from minimizing the exposure to radiation with better understanding and applications of the physics associated with fluoroscopic imaging to using alternative imaging modalities that do not use radiation.

Utility of Three-Dimensional Printed Model in Biventricular Repair of Complex Congenital Cardiac Defects: Case Report and Review of Literature.

Heterotaxy is a rare syndrome associated with cardiac complexity, anatomic variability and high morbidity and mortality. It is often challenging to visualize and provide an accurate diagnosis of the cardiac anatomy prior to surgery with the use of conventional imaging techniques. We report a unique case demonstrating how the use of three-dimensional (3D) cardiac printed model allowed us to better understand the anatomical complexity and plan a tailored surgical approach for successful biventricular repair in a patient with heterotaxy syndrome.

Role of Three-Dimensional Visualization Modalities in Medical Education.

For the past two decades, slide-based presentation has been the method of content delivery in medical education. In recent years, other teaching modalities involving three-dimensional (3D) visualization such as 3D printed anatomical models, virtual reality (VR), and augmented reality (AR) have been explored to augment the education experience. This review article will analyze the use of slide-based presentation, 3D printed anatomical models, AR, and VR technologies in medical education, including their benefits and limitations.

Impact of Obesity on Left Ventricular Thickness in Children with Hypertrophic Cardiomyopathy.

Obesity is associated with additional left ventricular hypertrophy (LVH) in adults with hypertrophic cardiomyopathy (HCM). It is not known whether obesity can lead to further LVH in children with HCM. Echocardiographic LV dimensions were determined in 504 children with HCM. Measurements of interventricular septal thickness (IVST) and posterior wall thickness (PWT), and patients' weight and height were recorded. Obesity was defined as a body mass index (BMI) ≥ 99th percentile for age and sex. IVST data was available for 498 and PWT data for 484 patients. Patient age ranged from 2 to 20 years (mean ± SD, 12.5 ± 3.9) and 340 (68%) were males. Overall, patient BMI ranged from 7 to 50 (22.7 ± 6.1). Obesity (BMI 18-50, mean 29.1) was present in 140 children aged 2-19.6 (11.3 ± 4.1). The overall mean IVST was 20.5 ± 9.6 mm and the overall mean PWT was 11.0 ± 8.4 mm. The mean IVST in the obese patients was 21.6 ± 10.0 mm and mean PWT was 13.3 ± 14.7 mm. The mean IVST in the non-obese patients was 20.1 ± 9.5 mm and mean PWT was 10.4 ± 4.3 mm. Obesity was not significantly associated with IVST (p = 0.12), but was associated with increased PWT (0.0011). Obesity is associated with increased PWT but not IVST in children with HCM. Whether obesity and its impact on LVH influences clinical outcomes in children with HCM needs to be studied.

Risk factors for lethal arrhythmic events in children and adolescents with hypertrophic cardiomyopathy and an implantable defibrillator: An international multicenter study.

BACKGROUND: Predictors of risk of lethal arrhythmic events (LAE) is poorly understood and may differ from adults in children with hypertrophic cardiomyopathy (HCM). OBJECTIVE: The purpose of this study was to determine predictors of LAE in children with HCM. METHODS: A retrospective data collection was performed on 446 children and teenagers 20 years and younger (290 [65%] male; mean age 10.1 ± 5.7 years) with idiopathic HCM from 35 centers. Patients were classified as group 1 (HCM with LAE) if having a secondary prevention implantable cardioverter-defibrillator (ICD) or primary prevention ICD with appropriate interventions or group 2 (HCM without LAE) if having a primary prevention ICD without appropriate interventions. RESULTS: There were 152 children (34%) in group 1 and 294 (66%) in group 2. Risk factors for group 1 by univariate analysis were septal thickness, posterior left ventricular (LV) wall thickness, lower LV outflow gradient, and Q wave > 3 mm in inferior electrocardiographic leads. Factors not associated with LAE were family history of SCD, abnormal blood pressure response to exercise, and ventricular tachycardia on ambulatory electrocardiographic monitoring. Risk factors for SCD by multivariate analysis were age at ICD placement (hazard ratio [HR] 0.9; P = .0025), LV posterior wall thickness z score (HR 1.02; P < .005), and LV outflow gradient < 30 mm Hg (HR 2.0; P < .006). LV posterior wall thickness z score ≥ 5 was associated with LAE. CONCLUSION: Risk factors for LAE appear different in children compared to adults. Conventional adult risk factors were not significant in children. Further prospective studies are needed to improve risk stratification for LAE in children with HCM.

Transseptal puncture using surgical electrocautery in children and adults with and without complex congenital heart disease.

BACKGROUND: Atrial transseptal puncture (TSP) for cardiac catheterization procedures remain challenging in children and adults with complex congenital heart disease (CHD). OBJECTIVES: We sought to evaluate our experience using radiofrequency (RF) current via surgical electrocautery needle for TSP to facilitate diagnostic and interventional procedures. METHODS: Retrospective chart review of all patients (pts) who underwent TSP using RF energy (10-25 W) via surgical electrocautery from three centers from January 2011 to January 2017 were evaluated. Echocardiograms were reviewed to define the atrial septum as normal and complex (thin aneurysmal, thick/fibrotic, synthetic patch material, and extra cardiac conduit). RESULTS: A total of 54 pts underwent 55 successful TSP. Median age was 12.5 years (1 day-54 years) and weight was 52.7 kg (2-162). Indications for TSP included; EP study and ablation procedures in structurally normal hearts (n = 24) and in complex atrial septum/CHD and structural heart disease pts (n = 30): Electrophysiology study and ablation in 4, diagnostic catheterization in 9, and interventional procedures in 17 pts were performed. Atrial TSP was successful in 54/55 (98%). Atrial perforation with tiny-small pericardial effusion not requiring intervention was noted in 2 pts. TSP was unsuccessful in one critically ill neonate with unobstructed TAPVR and restricted atrial septum who experienced cardiac arrest requiring CPR, ECMO, and emergent surgery. CONCLUSIONS: RF current delivery using surgical electrocautery for TSP is a feasible and an effective option in patients with complex CHD for diagnostic, interventional, and electrophysiology procedures.

Is Interarterial Course a Requisite for Ischemia in Anomalous Origin of Coronary Arteries?

Anomalous origin of the left main coronary artery from the noncoronary sinus (LCANS) is a rare variant of anomalous aortic origin of a coronary artery that is not characterized by an interarterial course. Despite the absence of an interarterial course, there are rare reports of LCANS presenting with sudden death, life-threatening arrhythmia, exercise-induced myocardial ischemia, premature ventricular contractions, and syncope. We report a patient with LCANS presenting with acute myocardial infarction who recovered completely with emergent surgical unroofing of the coronary artery.

Feasibility, accuracy, and safety of 3-dimensional electroanatomic mapping without fluoroscopy in patients with congenital heart defects.

BACKGROUND: Use of nonfluoroscopic 3-dimensional electroanatomic mapping (NF-3DEAM) in patients with congenital heart defects (CHDs) is not well reported. OBJECTIVE: The purpose of this study was to evaluate the feasibility, accuracy, and safety of NF-3DEAM in patients with CHDs. METHODS: Retrospective review of electrophysiologic study (EPS) in patients with CHD from 2009 to 2013 was conducted. Patients undergoing EPS with NF-3DEAM using the EnSite NavX system (St. Jude Medical) were included and those with fluoroscopy were excluded. Cardiac angiography performed in close proximity was matched with 3DEAM by proper aspect ratio using manual alignment by overlay images and comparing distances between cardiac landmarks using Pearson correlation coefficient and intraclass correlation. Success and complications were reviewed. RESULTS: Three-dimensional electroanatomic mapping and angiograms were compared in 48 EPS (45 patients); 13 patients with intracardiac leads, quiescent chambers indicating significant scarring, and who required transseptal puncture were excluded. Indications for EPS included documented tachyarrhythmia and preoperative mapping. Mean age was 25.3 ± 9.8 years. Simple CHDs (isolated shunt lesions or valvular lesions) were identified in 13 studies (27%) and complex CHDs (others) were identified in 35 studies (73%). Ablations were performed in 25 studies (52%). Average time to obtain right atrial geometry was 25.3 minutes (range 14-47 minutes) and right ventricular geometry was 22.8 minutes (range 12-35 minutes). Pearson correlation coefficient and intraclass correlation of cardiac landmarks were 0.90 and 0.80, respectively. Anatomic landmarks, mapping, and ablation were accurate in all 3DEAMs. No complications were recorded. CONCLUSION: NF-3DEAM is feasible, safe, and accurate in CHD patients without extensive scarring, intracardiac leads, and need for transseptal puncture.

Usefulness of vascular stenting with and without transvenous pacing leads for vena caval obstruction among children and adults with repaired congenital heart disease.

Vena caval obstruction (VCO) is a common complication after vascular manipulation for congenital heart disease. Long-term efficacy of stent therapy for relief of VCO and long-term stent patency with and without intrastent transvenous pacing leads (TPLs) is not well described. This was a retrospective review of patients treated for VCO, including those who received intrastent TPLs, between 1995 and 2012. Patient demographics, diagnoses, vascular pressure gradients, and vessel diameters were analyzed. Forty-one patients (mean age 23.5 ± 10.3 years) with and without congenital heart disease underwent stent implantation, 26 of whom also received intrastent TPLs. Short-term stent implantation success in relieving obstructions was 93%. Poststent vascular pressure gradients and percentage vascular narrowing significantly improved (from 6.2 ± 4.5 to 1.1 ± 1.6 mm Hg and from 63.1 ± 19.5% to 18.0 ± 17.1%, respectively, p <0.05). On follow-up in 38 of 41 patients from 0.2 to 18 years (median 6.0), all survived; 6 (14%) required stent reintervention. Freedom from reintervention was 87% at 15 years. Patients with short-term procedural failure were at higher risk for stent reintervention. Among 27 patients with intrastent TPLs, freedom from reintervention was 96%. In 26 patients with follow-up catheterization, intrastent intimal proliferation was not significantly associated with TPL but was higher in the superior vena cava-innominate vein junction compared with other stent locations (p <0.05). In conclusion, stent therapy for VCO can be successfully and safely performed with good long-term results. Pre-pacing lead stent placement for VCO is effective in allowing TPL placement with encouraging long-term patency.

Limb ischaemia and below-knee amputation following life-saving patent ductus arteriosus stent in a critically ill infant.

Limb ischaemia is a rare but catastrophic complication related to cardiac catheterisation. We report an infant weighing 3 kg with unrepaired tricuspid atresia type 1b, small patent ductus arteriosus, and ventricular septal defect presenting with cardiogenic shock owing to progressively reduced pulmonary blood flow from closing ventricular septal defect and patent ductus arteriosus. An emergency palliative ductal stent was successfully placed with marked clinical improvement. However, acute limb ischaemia developed necessitating above-knee amputation, despite medical management and vascular surgery. The cause of limb loss in our patient was catheterisation-related vascular injury causing arterial dissection-arterial thrombosis in the presence of shock and coagulopathy. This report emphasises the complexity in managing limb ischaemia associated with coagulopathy and highlights the importance of early recognition of reduced pulmonary flow in a single ventricle patient. Timely elective placement of a surgical systemic to pulmonary shunt would prevent catastrophic clinical presentation of compromised pulmonary flow and avoid the need for an emergent life-saving intervention and its associated complications.

The asymptomatic teenager with an abnormal electrocardiogram.

Use of medications for attention-deficit hyperkinetic disorder and preparticipation sports physical examination has led to an increase in number of electrocardiograms (ECG) performed during adolescence. Interpreting ECGs in children and young adults must take into account the evolutionary changes with age and the benign variants, which are usually not associated with heart disease. It is crucial for primary-care providers to recognize the changes on ECG associated with heart disease and risk of sudden death. In this article, the significance, sensitivity, specificity, and the diagnostic workup of these findings in the asymptomatic teenager are discussed.

An international multicenter study comparing arrhythmia prevalence between the intracardiac lateral tunnel and the extracardiac conduit type of Fontan operations.

OBJECTIVE: The study objective was to determine whether the extracardiac conduit Fontan confers an arrhythmia advantage over the intracardiac lateral tunnel Fontan. METHODS: This multicenter study of 1271 patients compared bradyarrhythmia (defined as need for pacing) and tachyarrhythmia (defined as needing antiarrhythmic therapy) between 602 patients undergoing the intracardiac Fontan and 669 patients undergoing the extracardiac Fontan. The median age at the time of the Fontan procedure was 2.1 years (interquartile range, 1.6-3.2 years) for the intracardiac group and 3.0 years (interquartile range, 2.4-3.9) for the extracardiac group (P < .0001). The median follow-up was 9.2 years (interquartile range, 5-12.8) for the intracardiac group and 4.7 years (interquartile range, 2.8-7.7) for the extracardiac group (P < .0001). RESULTS: Early postoperative (<30 days) bradyarrhythmia occurred in 24 patients (4%) in the intracardiac group and 73 patients (11%) in the extracardiac group (P < .0001). Early postoperative (<30 days) tachyarrhythmia occurred in 32 patients (5%) in the intracardiac group and 53 patients (8%) in the extracardiac group (P = not significant). Late (>30 days) bradyarrhythmia occurred in 105 patients (18%) in the intracardiac group and 63 patients (9%) in the extracardiac group (P < .0001). Late (>30 days) tachyarrhythmia occurred in 58 patients (10%) in the intracardiac group and 23 patients (3%) in the extracardiac group (P < .0001). By multivariate analysis factoring time since surgery, more patients in the extracardiac group had early bradycardia (odds ratio, 2.9; 95% confidence interval, 1.8-4.6), with no difference in early tachycardia, late bradycardia, or late tachycardia. CONCLUSIONS: Overall arrhythmia burden is similar between the 2 groups, but the extracardiac Fontan group had a higher incidence of early bradyarrhythmias. There was no difference in the incidence of late tachyarrhythmias over time between the 2 operations. Therefore, the type of Fontan performed should be based on factors other than an anticipated reduction in arrhythmia burden from the extracardiac conduit.

Catheterization-based intervention in low birth weight infants less than 2.5 kg with acute and long-term outcome.

BACKGROUND: The number of low birth weight infants with congenital heart disease is increasing and catheterizations may have an increased risk for mortality and morbidity. OBJECTIVES: We investigate the outcome and complications of cardiac catheterizations in infants weighing < 2.5 kg. METHODS: Retrospective review of catheterization records from 1995 to 2010 in infants weighing < 2.5 kg. The demographics, procedure, outcome, and follow-up data were collected. RESULTS: Of 101 catheterizations performed in 88 patients, 45 (45%) catheterizations were interventional. Balloon atrial septostomy (n = 23), pulmonary valvuloplasty (14), aortic valvuloplasty (4), stent placement (3), balloon angioplasty (2), and temporary pacemaker insertion (1) were successfully performed. Balloon atrial septostomy was performed with pulmonary or aortic valvuloplasty in two catheterizations. Infants < 2.5 kg had higher significant adverse event rate that those 2.5-3.5 kg (13% versus 6.6%, P < 0.05). No procedural death was noted. Significant adverse events (n = 13) included cardiopulmonary resuscitation three, vascular six, arrhythmia three, and apnea requiring intubation one. On median follow-up of 3 years (0.03 to 14), n = 69, mortality rate was 36%. In six patients with valvar pulmonary stenosis with median follow-up of 6 years (0.75-13), four (67%) did not require re-intervention. Of two patients with aortic stenosis, one did not require repeat intervention for 6 years (last follow-up). CONCLUSION: Interventional catheterization is feasible with low procedural morbidity and mortality in high risk infants < 2.5 kg. Catheterization primarily serves as a palliative procedure to stabilize infants for definitive treatment. Balloon valvuloplasty may be effective for isolated valvar pulmonary stenosis in infants < 2.5 kg.

Pacing in children.

The implantation of cardiac pacing devices in children and young adults can be challenging and different from the adult population due to their smaller size, their longer life expectancy, and anatomical variations associated with congenital heart defects. A knowledge of indications, pacing leads and devices, anatomical variations, and the technical skills are important for those who implant and care for children with pacemakers. In this review we attempt to discuss these specific points of cardiac pacing in children and young adults.

Cardiac pacing and defibrillation in children and young adults.

The population of children and young adults requiring a cardiac pacing device has been consistently increasing. The current generation of devices are small with a longer battery life, programming capabilities that can cater to the demands of the young patients and ability to treat brady and tachyarrhythmias as well as heart failure. This has increased the scope and clinical indications of using these devices. As patients with congenital heart disease (CHD) comprise majority of these patients requiring devices, the knowledge of indications, pacing leads and devices, anatomical variations and the technical skills required are different than that required in the adult population. In this review we attempt to discuss these specific points in detail to improve the understanding of cardiac pacing in children and young adults.

Transcatheter retrieval and repositioning of embolized stent from the right ventricle in an infant.

Intracardiac stent embolization is a challenging complication in a small infant. A Palmaz stent was placed across the atrial septum in a 3-month-old boy to relieve symptoms of right-side heart failure. On routine chest radiography one week later, the stent was found to have embolized into the right ventricle. The stent was retrieved and repositioned by means of transcatheter technique, without subsequent complications. We found this method to be a viable alternative to surgery in a high-risk infant. To our knowledge, this is the first report of the successful transcatheter retrieval and repositioning of an expandable intravascular stent from an intraventricular position in an infant.

Primary endocardial fibroelastosis presenting in a young child as incessant ventricular tachycardia and dilated cardiomyopathy.

Endocardial fibroelastosis is a cardiomyopathy not commonly seen in the present age. We describe the case of a 4-year-old girl who presented with sustained incessant ventricular tachycardia, a severely dilated left ventricle, and cardiac dysfunction refractory to all medical management and even to ablation; she eventually underwent cardiac transplantation. The diagnosis was made only after histopathologic examination of the explanted heart showed clear evidence of endocardial fibroelastosis. Through this report, we would like to highlight the fact that primary endocardial fibroelastosis can masquerade as idiopathic dilated cardiomyopathy and that associated frequent premature ventricular contractions and nonsustained ventricular tachycardia require close monitoring. Progressive ventricular dilation and ventricular dysfunction can convey a poor prognosis. Sustained recalcitrant ventricular tachycardia in these patients can be a life-threatening event that requires emergent mechanical support and heart transplantation.

The study of antiarrhythmic medications in infancy (SAMIS): a multicenter, randomized controlled trial comparing the efficacy and safety of digoxin versus propranolol for prophylaxis of supraventricular tachycardia in infants.

BACKGROUND: Supraventricular tachycardia (SVT) is one of the most common conditions requiring emergent cardiac care in children, yet its management has never been subjected to a randomized controlled clinical trial. The purpose of this study was to compare the efficacy and safety of the 2 most commonly used medications for antiarrhythmic prophylaxis of SVT in infants: digoxin and propranolol. METHODS AND RESULTS: This was a randomized, double-blind, multicenter study of infants <4 months with SVT (atrioventricular reciprocating tachycardia or atrioventricular nodal reentrant tachycardia), excluding Wolff-Parkinson-White, comparing digoxin with propranolol. The primary end point was recurrence of SVT requiring medical intervention. Time to recurrence and adverse events were secondary outcomes. Sixty-one patients completed the study, 27 randomized to digoxin and 34 to propranolol. SVT recurred in 19% of patients on digoxin and 31% of patients on propranolol (P=0.25). No first recurrence occurred after 110 days of treatment. The 6-month recurrence-free status was 79% for patients on digoxin and 67% for patients on propranolol (P=0.34), and there were no first recurrences in either group between 6 and 12 months. There were no deaths and no serious adverse events related to study medication. CONCLUSIONS: There was no difference in SVT recurrence in infants treated with digoxin versus propranolol. The current standard practice may be treating infants longer than required and indicates the need for a placebo-controlled trial. Clinical Trial Registration Information- http://clinicaltrials.gov; NCT-00390546.