Double Ventricular Response with Aberrant Conduction Leading to Ventricular Dysfunction.

Double ventricular response (DVR), where a single P wave results in two QRS complexes, is a rare presentation of dual AV node physiology. It has been associated with ventricular dysfunction in the setting of incessant tachycardia. We present the case of an otherwise healthy adolescent who had frequent DVR without tachycardia leading to left ventricular dysfunction. Slow pathway modification led to a significant reduction in ectopy and normalization of ventricular function. This highlights that DVR without tachycardia might lead to ventricular dysfunction in pediatric patients. Slow pathway modification with reduction of ectopy may be sufficient to restore ventricular function.

Incidence and outcome of arrhythmias and electrical disease in patients with Trisomy 18.

Patients with Trisomy 18 have a high incidence of cardiac anomalies and are associated with early death. Because of early mortality, electrical system disease and arrhythmia has been difficult to delineate and the incidence remain unknown. We sought to describe the association and clinical outcomes of electrical system disease and cardiac tachy-arrhythmias in patients with Trisomy 18. This was a retrospective, single institutional study. All patients with Trisomy 18 were included in the study. Patient characteristics, congenital heart disease (CHD), conduction system and clinical tachy-arrhythmia data were collected on all patients. Outcomes including cardiac surgical interventions, electrical system interventions and death were collected until the time of study. Patients with tachy-arrhythmias/electrical system involvement were compared to those without to identify potential associated variables. A total of 54 patients with Trisomy 18 were included in analysis. The majority of patients was female and had associated CHD. AV nodal conduction system abnormalities with either first or second degree AV block were common (15%) as was QTc prolongation (37%). Tachy-arrhythmias were common with 22% of patients having at least one form of tachy-arrhythmia and associated with concomitant conduction system disease (p = 0.002). Tachy-arrhythmias were typically treatable with monitoring or medication with eventual resolution without need for procedural intervention. Although early death was common, there were no causes of death associated with tachy-arrhythmia or conduction system disease. In conclusion, patients with Trisomy 18 have a high incidence of conduction system abnormalities and burden of clinical tachy-arrhythmias. Although frequent, electrical system disease did not affect patient outcome or difficultly of care delivery.

EKG Abnormalities in a Youth Athlete Following COVID-19: It's Not Always Myocarditis!

COVID-19 associated myocarditis following mild infections is rare while incidental findings may be more common. A young athlete fully recovered from a mild COVID-19 infection presented with inferolateral T-wave inversions and left ventricular hypertrophy on imaging. Exercise testing aided in correctly diagnosing the patient with masked systolic hypertension.

Patient understanding of disease and the use and outcome of implantable cardioverter defibrillators in hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is the most common cause of sudden cardiac death (SCD) in young individuals. Implantable cardioverter defibrillators (ICD) are the primary therapy for sudden death prevention; however, are associated with both physical and psychological complications. We sought to determine factors associated with ICD understanding and patient satisfaction. This was a cross-sectional study, using patient/parent answered questionnaires distributed to patients enrolled in the Hypertrophic Cardiomyopathy Association. Patient characteristics and satisfaction data were obtained via questionnaire. Patients were compared based on age at diagnosis and presence of ICD. ICD patients with high satisfaction were compared to those with low satisfaction to determine factors associated with poor satisfaction. A total of 538 responses were obtained (53 ± 16 years); 46% were females. Seventy patients (13%) were diagnosed with HCM < 18 years of age and 356 (66%) had an ICD. Compared to those without an ICD, patients with ICDs were younger at age of diagnosis (P = 0.001) and time of study (P = 0.008). Patients with ICDs were more likely to have presented with syncope and have family history of ICD, SCD, or HCM-related death. Nineteen patients (5%) felt that issues surrounding their ICD outweighed its benefit. Compared to patients with a favorable satisfaction, the only significant difference was the preimplant ICD discussion (P < 0.001) and history of lead replacement (P = 0.01). In conclusion, the majority of HCM patients with ICDs are satisfied with their ICD management and feel the benefits of ICDs outweigh issues associated with ICDs. Additionally, these data highlight the importance of the preimplant patient-physician discussion around the need for ICD prior to implantation.

Sedation methods for transthoracic echocardiography in children with Trisomy 21-a retrospective study.

BACKGROUND: Many children with Trisomy 21 have neurologic or behavioral problems that make it difficult for them to remain still during noninvasive imaging studies, such as transthoracic echocardiograms (TTEcho). Recently, intranasal dexmedetomidine sedation has been introduced for this purpose. However, dexmedetomidine has been associated with bradycardia. Children with Trisomy 21 have been reported to have a higher risk of bradycardia and airway obstruction with sedation or anesthesia compared to children without Trisomy 21. OBJECTIVE: Our aim was to quantify the incidence of age-defined bradycardia and other adverse effects in patients with Trisomy 21 under sedation for TTEcho using a variety of sedation and anesthesia techniques available and utilized at our institution in this challenging patient population, including intranasal dexmedetomidine, oral pentobarbital, general anesthesia with propofol, and general anesthesia with sevoflurane. Our primary hypothesis was that intranasal dexmedetomidine sedation would result in a significantly higher risk of bradycardia in patients with Trisomy 21, compared with other sedative or anesthetic regimens. METHODS: This is a retrospective, observational study of 147 consecutive patients with Trisomy 21 who were sedated or anesthetized for transthoracic echocardiography. Efficacy of sedation was defined as no need for rescue sedation or conversion to an alternate technique. Lowest and highest heart rate, systolic blood pressure, oxygen saturation, and PR interval from formal electrocardiograms were extracted from the electronic medical record. These data were compared to age-defined normal values to determine adverse events. RESULTS: Four methods of sedation or anesthesia were utilized to perform sedated transthoracic echocardiography: general anesthesia with sevoflurane by mask, general anesthesia with sevoflurane induction followed by intravenous propofol maintenance, oral pentobarbital, and intranasal dexmedetomidine. Intranasal dexmedetomidine 2.5 mcg·kg-1 was an effective sedative as a single dose for TTEcho in 37 of 41 (90%) cases. Oral pentobarbital 5 mg·kg-1 as a single dose for young children with Trisomy 21 was effective in 55 of 75 (73%) cases. Intranasal dexmedetomidine sedation was not associated with a significantly higher risk of bradycardia in patients with Trisomy 21, compared with other sedative or anesthetic regimens, when compared to oral pentobarbital for patients under 2 years of age and general anesthesia for children 3 years and older. The two general anesthesia groups showed lowest heart rates of 66.9 ± 15.9 min-1 for sevoflurane and 69.0 ± 11.5 min-1 for sevoflurane-propofol. Hypotension was present in all groups ranging between an incidence of 56% in the sevoflurane group to 11% in the oral pentobarbital group. Oxygen saturation and clinically significant desaturation occurred in 14% of the oral pentobarbital group. CONCLUSION: Intranasal dexmedetomidine sedation was not associated with a significantly higher risk of bradycardia in patients with Trisomy 21, compared with other sedative or anesthetic regimens.

Cardiovascular risk factors and cardiac disorders in long-term survivors of pediatric liver transplantation.

The MetS and cardiovascular disease are leading causes of late morbidity in adult liver transplantation recipients; however, limited data are available in pediatric liver transplantation. A single-center retrospective review was undertaken for patients who had a liver transplantation before 18 yr of age and were >5 yr post-transplantation, to study the prevalence of MetS, its components, and cardiac disorders. Fifty-eight patients were included in the study with a mean age at transplantation of 6.3 ± 6.1 yr and mean follow-up of 14.1 ± 6.0 yr. Of the study group, 41.4% were overweight or obese, with ongoing prednisone use and increased duration of follow-up being significant risk factors. Fifty-three patients had sufficient data for determining MetS, which was present in 17% of the patients. Although the prevalence of MetS is low in pediatric liver transplant recipients, it is associated with CKD and prednisone therapy (p < 0.05). Echocardiography data were available for 23 patients, of whom 43.4% had LVH and 13% had evidence of PH. The spectrum of cardiac disorders in this population is much wider than in adults.

Compound heterozygous mutations in the SCN5A-encoded Nav1.5 cardiac sodium channel resulting in atrial standstill and His-Purkinje system disease.

An 11-year-old girl on evaluation for syncope was found to have progressive sinus node dysfunction and His-Purkinje system disease with atrial standstill. Genetic analysis revealed compound heterozygous mutations of the SCN5A gene in a novel combination.

Epidemiology of Postoperative Junctional Ectopic Tachycardia in Infants Undergoing Cardiac Surgery.

BACKGROUND: Junctional ectopic tachycardia (JET) complicates congenital heart surgery in 2% to 8.3% of cases. JET is associated with postoperative morbidity in single-center studies. We used the Pediatric Cardiac Critical Care Consortium data registry to provide a multicenter epidemiologic description of treated JET. METHODS: This is a retrospective study (February 2019-August 2022) of patients with treated JET. Inclusion criteria were (1) <12 months old at the index operation, and (2) treated for JET <72 hours after surgery. Diagnosis was defined by receiving treatment (pacing, cooling, and medications). A multilevel logistic regression analysis with hospital random effect identified JET risk factors. Impact of JET on outcomes was estimated by margins/attributable risk analysis using previous risk-adjustment models. RESULTS: Among 24,073 patients from 63 centers, 1436 (6.0%) were treated for JET with significant center variability (0% to 17.9%). Median time to onset was 3.4 hours, with 34% present on admission. Median duration was 2 days (interquartile range, 1-4 days). Tetralogy of Fallot, atrioventricular canal, and ventricular septal defect repair represented >50% of JET. Patient characteristics independently associated with JET included neonatal age, Asian race, cardiopulmonary bypass time, open sternum, and early postoperative inotropic agents. JET was associated with increased risk-adjusted durations of mechanical ventilation (incidence rate ratio, 1.6; 95% CI, 1.5-1.7) and intensive care unit length of stay (incidence rate ratio, 1.3; 95% CI, 1.2-1.3), but not mortality. CONCLUSIONS: JET is treated in 6% of patients with substantial center variability. JET contributes to increased use of postoperative resources. High center variability warrants further study to identify potential modifiable factors that could serve as targets for improvement efforts to ameliorate deleterious outcomes.

Atrial arrhythmias following lung transplant: a single pediatric center experience.

Background: Outcomes after lung transplant (LTx) in children have slowly improved. Although atrial arrhythmia (AA) is a common and adverse complication following LTx among adults, there is limited data on pediatric recipients. We detail our pediatric single-center experience while providing further insights on occurrence and management of AA following LTx. Methods: A retrospective analysis of LTx recipients at a pediatric LTx program from 2014 to 2022 was performed. We investigated timing of occurrence and management of AA following LTx, and its effect on post-LTx outcome. Results: Three out of nineteen (15%) pediatric LTx recipients developed AA. The timing of occurrence was 9-10 days following LTx. Those patients in the older age group (age >12 years old) were the only ones who developed AA. Developing AA did not have a negative effect on hospital stay duration or short-term mortality. All LTx recipients with AA were discharged home on therapy that was discontinued at 6 months for those who was on mono-therapy without recurrence of AA. Conclusions: AA is an early post-operative complication in older children and younger adults undergoing LTx at a pediatric center. Early recognition and aggressive management can mitigate any morbidity or mortality. Future investigations should explore factors that place this population at risk for AA in order to prevent this complication post-operatively.

Predictors and outcomes of heart block during surgical stage I palliation of patients with a single ventricle: A report from the NPC-QIC.

BACKGROUND: Mortality in cohorts with a single ventricle remains high with multiple associated factors. The effect of heart block during stage I palliation remains unclear. OBJECTIVE: The purpose of this study was to study patient and surgical risks of heart block and its effect on 12-month transplant-free survival in patients with a single ventricle. METHODS: Patient, surgical, outcome data and heart block status (transient and permanent) were obtained from the National Pediatric Cardiology Quality Improvement Collaborative single ventricle database. Bivariate analysis was performed comparing patients with and without heart block, and multivariate modeling was used to identify variables associated with block. One-year outcomes were analyzed to identify variables associated with lower 12-month transplant-free survival. RESULTS: In total, 1423 patients were identified, of whom 28 (2%) developed heart block (second degree or complete) during their surgical admission. Associated risk factors for block included heterotaxy syndrome (odds ratio [OR] 6.4) and atrial flutter/fibrillation (OR 3.8). Patients with heart block had lower 12-month survival, though only in patients with complete heart block as opposed to second degree block. At 12 months of age, 43% (12/28) of patients with heart block died and were more likely to experience mortality at 12 months than patients without block (OR 4.9; 95% confidence interval 1.4-17.5; P = .01). CONCLUSION: Although rare, complete heart block after stage I palliation represents an additional risk of poor outcomes in this high-risk patient population. Heterotaxy syndrome was the most significant risk factor for the development of heart block after stage I palliation. The role of transient block in outcomes and potential rescue with long-term pacing remains unknown and requires additional study.

Outcomes of Implantable Loop Monitoring in Patients <21 Years of Age.

Rhythm-symptom correlation in pediatric patients with syncope/palpitations or at risk cohorts can be difficult, but important given potential associations with treatable or malignant arrhythmia. We sought to evaluate the use, efficacy and outcomes of implantable loop recorders (ILR) in pediatrics. We conducted a retrospective study of pediatric patients (<21 years) with implanted ILR. Patient/historical characteristics and ILR indication were obtained. Outcomes including symptom documentation, arrhythmia detection and ILR based changes in medical care were identified. Comparison of outcomes were performed based on implant indication. Additional sub-analyses were performed in syncope-indication patients comparing those with and without changes in clinical management. A total of 116 patients with ILR implant were identified (79 syncope/37 other). Symptoms were documented 58% of patients (syncope 68% vs nonsyncope 35%; p = 0.002). A total of 37% of patients had a documented clinically significant arrhythmia and 25% of patients had a resultant change in clinical management independent of implant indication. Arrhythmia type was dependent on implant indication with nonsyncope patients having more ventricular arrhythmias. Pacemaker/defibrillator implantation and mediation management were the majority of the clinical changes. In conclusion, IRL utilization in selected pediatric populations is associated with high efficacy and supports clinical management. ILR efficacy is similar regardless of indication although patients with nonsyncope indications had a higher frequency of ventricular arrhythmias as opposed to asystole and heart block in syncope indications. The majority of arrhythmic findings occurred in the first 12 months, and new technology that would allow for less invasive monitoring for 6 to 12 months may be of value.

Fetal intracranial calcification: pseudo-TORCH phenotype and discussion of related phenotypes.

Fetal intracranial calcification (ICC) noted during antenatal imaging poses a diagnostic challenge. Although this presentation is most commonly associated with intrauterine infection, non-infectious causes of fetal ICC have been reported and include metabolic, genetic, or hemodynamic conditions. We report on a patient with antenatally detected extensive ICC, in whom postnatal imaging revealed a distinctive band-like ICC with abnormal gyral pattern and a negative serology for TORCH infections. Such a constellation of findings have been previously described under the terminology of "pseudo-TORCH phenotype," and we posit that our patient represents this entity. Our patient had unreported dysmorphic features, which expands the phenotypic spectrum of this recently described heterogenous condition. In addition we report on the progression of the phenotype both clinically and radiologically. In view of the limited information available for the differential diagnosis of fetal ICC, we also review the available literature on this topic.

Evaluation and Management of Common Neonatal Arrhythmias.

Neonates can have different types of arrhythmias that range from benign to life-threatening. The evaluation, approach to acute presentation, and long-term management depend on correct identification of the arrhythmia. A systematic approach to analyzing the electrocardiogram and the telemetry monitor, if available, is often sufficient to diagnose the type of arrhythmia.

Adams-Oliver syndrome: Additions to the clinical features and possible role of BMP pathway.

We report on a patient with Adams-Oliver syndrome, a condition characterized by scalp and limb defects. In addition we noted in our patient a significant delay in the bone age and an abnormal distal phalanx in one of her fingers manifesting clinically as a broad finger tip. Both these features hitherto unreported add to the phenotypic spectrum of the condition. The underlying etiopathogenesis of this condition has remained in the domain of hypothesis, with none being conclusive. Based on the characteristic features of AOS and our report of delayed bone age, we postulate a role played by the bone morphogenetic protein pathway in the causation of this enigmatic condition. In the background of this postulation and the report of an unusual hand anomaly, a literature review on the various pathogenetic mechanisms and anomalies of the hand reported in AOS is presented.

A Standardized Cardiac Protocol for Pediatric Drug Ingestion Hospital Admissions.

To optimize patient resource utilization and safety, we created a standard-of-care guideline for pediatric drug ingestion hospital admissions. METHODS: A multidisciplinary committee developed specific telemetry guidelines for pediatric drug ingestion hospital admissions at a tertiary pediatric hospital. The guidelines stipulated inpatient admission with telemetry monitoring for the following criteria: (1) corrected QT interval (interval between the Q wave and T wave on a standard EKG)≥ 500 ms, (2) ingestion of an antiarrhythmic medication, or (3) ingestion of a tricyclic antidepressant. We created guidelines for electrocardiogram frequency for nontelemetry admissions. We implemented these guidelines in November 2015 in partnership with the Emergency Medicine Department and Poison Control Center. We reviewed medical records of all these admissions between January 1, 2015, and July 31, 2016, and divided patients into preintervention (January 1, 2015 to November 30, 2015) and postintervention (December 1, 2015 to July 31, 2016) groups. We used statistical process control charts and methodology to monitor changes over time. RESULTS: There were a total of 622 drug ingestion admissions during the study period. We admitted 69 patients (11%) to the cardiac acute care unit (CACU) for telemetry monitoring. The preintervention period included 61 admissions (5.5 CACU admissions per month). The postintervention period included 8 admissions (1.1 CACU admissions per month). This difference reflects an overall absolute decrease of 87%. There was no evidence of an increase in the rate of intensive care unit utilization, rapid response events, or adverse events in the postintervention period. CONCLUSIONS: A standardized admission protocol for pediatric drug ingestions can safely improve resource utilization.

Ventricular force-frequency relationships during biventricular or multisite pacing in congenital heart disease.

BACKGROUND: Traditional indices to evaluate biventricular (BiV) pacing are load dependent, fail to assess dynamic changes, and may not be appropriate in patients with congenital heart disease (CHD). We therefore measured the force-frequency relationship (FFR) using tissue Doppler-derived isovolumic acceleration (IVA) to assess the dynamic adaption of the myocardium and its variability with different ventricular pacing strategies. METHODS: This was a prospective pilot study of pediatric and young adult CHD patients with biventricular or multisite pacing systems. Color-coded myocardial velocities were recorded at the base of the systemic ventricular free wall. IVA was calculated at resting heart rate and with incremental pacing. FFR curves were obtained by plotting IVA against heart rate for different ventricular pacing strategies. RESULTS: Ten patients were included (mean: 22 ± 7 years). The FFR identified a best and worst ventricular pacing strategy for each patient, based on the AUC at baseline, submaximal, and peak heart rates (P < .001). However, there was no single best ventricular pacing strategy that was optimal for all patients. Additionally, the best ventricular pacing strategy often differed within the same patient at different heart rates. CONCLUSION: This novel assessment demonstrates a wide variability in optimal ventricular pacing strategy. These inherent differences may play a role in the unpredictable clinical response to BiV pacing in CHD, and emphasizes an individualized approach. Furthermore, the optimal ventricular pacing varies with heart rate within individuals, suggesting that rate-responsive ventricular pacing modulation may be required to optimize ventricular performance.