Fetal Heart Rate < 3rd Percentile for Gestational Age Can Be a Marker of Inherited Arrhythmia Syndromes.

BACKGROUND: Repeated fetal heart rates (FHR) < 3rd percentile for gestational age (GA) with 1:1 atrioventricular conduction (sinus bradycardia) can be a marker for long QT syndrome. We hypothesized that other inherited arrhythmia syndromes might present with fetal sinus bradycardia. METHODS: We reviewed pregnancies referred with sinus bradycardia to the Colorado Fetal Care Center between 2013 and 2023. FHR/GA data, family history, medication exposure, normalized isovolumic contraction times (n-IVRT), postnatal genetic testing, and ECGs at 4-6 weeks after birth were reviewed. RESULTS: Twenty-nine bradycardic subjects were evaluated by fetal echocardiography. Five were lost to follow-up, one refused genetic testing, and one had negative genetic testing for any inherited arrhythmia. Six had non-genetic causes of fetal bradycardia with normal prenatal n-IVRT and postnatal QTc. Thirteen carried pathogenic variants in RYR2 (n = 2), HCN4 (n = 2), KCNQ1 (6), and other LQTS genes (n = 4). The postnatal QTc was <470 ms in subjects with RYR2, HCN4, and two of those with KCNQ1 mutations, and >470 ms in subjects with CALM 2, KCNH2, SCN5A, and four of those with KCNQ1 mutations. LQTS and RYR2 mutations were associated with prolonged n-IVRT, but HCN4 was not. Two fetuses died in utero with variants of uncertain significance (CACNA1 and KCNE1). Cascade testing uncovered six affected but undiagnosed parents and confirmed familial inheritance in five. CONCLUSION: In addition to heralding LQTS, repeated FHR < 3rd percentile for GA is a risk factor for other inherited arrhythmia syndromes. These findings suggest that genetic testing should be offered to infants with a history of FHR < 3rd percentile for GA even if the postnatal ECG demonstrates a normal QTc interval.

A Prospective Evaluation of Arrhythmias in a Large Tertiary Neonatal Intensive Care Unit.

Arrhythmias in the neonatal period are common and can be classified as bradyarhythmias and tachyarrhythmias and as benign or non-benign. Neonatal arrhythmias are further differentiated between those with abnormalities in generation (non-sinus) and those with abnormalities in propagation. Because the neonatal myocardium is immature and operates at the peak of the Starling curve, significant changes in heart rate can result in a decline in cardiac output and compromise end-organ perfusion. This is especially true for premature neonates, those critically ill, or those with concomitant congenital heart disease. While sustained arrhythmias are frequently witnessed and recorded in tertiary neonatal intensive care units (NICU) very little data exist on the observance of non-sustained brady- or tachyarrhythmias in this cohort. No prospective study has been performed on all neonates admitted to a large tertiary NICU throughout their entire stay. The purpose of this study was to prospectively evaluate the prevalence and type of arrhythmias in a large NICU population from admission to discharge. All neonates admitted to the NICU at Inova Children's Hospital at Inova Fairfax Medical Campus between January 1, 2021 and April 1, 2021 were prospectively evaluated from admission to hospital discharge via continuous bedside monitoring reviewed every 24 h. Concerning telemetry strips were reviewed by two team members as well as the senior electrophysiologist. Two-hundred and one neonates (mean gestational age = 344/7 weeks) were enrolled in the study. Admission length ranged from 1 to 195 days (total of 5624 patient days, median 16 days). Overall, 68% (N = 137) of admissions had one or more arrhythmias, the most common of which was sinus tachycardia (65%, N = 130), followed by sinus bradycardia (30%, N = 60). Clinically relevant arrhythmias were diagnosed in 6.5% of neonates. During the study period there were four deaths, none of which were directly attributable to a primary arrhythmia. Approximately 68% of neonates exhibited at least one arrhythmia. Although the vast majority of these arrhythmias were benign, clinically relevant arrhythmias were observed in 6.5%. Patients admitted to the NICU appear to have a relatively high burden of benign arrhythmias, but a relatively low burden of pathologic arrhythmias.

Use of the NobleStitch™ EL for the treatment of patients with residual right-to-left shunt following device closure of PFO.

The unique design of the NobleStitch™ EL allows it to be used to close residual defects following failed device PFO closure without impacting the integrity of previously placed double-disk Gore occluders.

Newer risk assessment strategies in hypertrophic cardiomyopathy.

PURPOSE OF REVIEW: The present article serves to review current risk assessment guidelines for sudden cardiac death (SCD) in patients with hypertrophic cardiomyopathy (HCM) and to discuss how these guidelines can be applied to patients with childhood HCM. New diagnostic techniques that could lead to more accurate risk assessment tools are also discussed. RECENT FINDINGS: Current guidelines for risk assessment in childhood HCM are extrapolated from adult guidelines and lack background research to validate their use. Continuous variables, such as wall thickness, are converted to binary variables, which is particularly concerning in pediatric patients' where weight gain and linear growth is likely to lead to more significant hemodynamic changes in shorter periods of time. Some studies have even shown that risk factors concerning in adults may actually be protective in pediatric patients. Additionally, large gaps still remain between genotype and phenotype expression in HCM. SUMMARY: A better understanding of the relationship between cause, phenotype, and outcomes is needed to truly be able to determine risk for SCD in childhood HCM. Larger studies, including newer technologies and quantitative models, similar to the European HCM Risk-SCD model, which allows for a quantitative risk diagnosis, are needed as well.

Challenge of managing opposing rhythms in a mother and fetus.

INTRODUCTION: We report a case of a fetus with complex congenital heart disease and supraventricular tachycardia in the setting of maternal high grade atrioventricular block at 26 weeks' gestation. METHODS AND RESULTS: Electroanatomic mapping allowed successful implantation of a permanent pacemaker to provide adequate back-up pacing in the mother with zero radiation exposure, thus allowing safe delivery of transplacental anti-arrhythmic medications to reduce the fetal arrhythmia burden and optimize the fetal ventricular rate. CONCLUSION: This is the first reported case of using electroanatomic mapping, with zero fluoroscopy use, for pacemaker lead placement and for a novel indication.

Bacterial Endocarditis Manifesting as Outflow Tract Obstruction in Two Patients Implanted With Percutaneous Prosthetic Pulmonary Valves.

Recent reports on bacterial infections occurring in patients with transcatheter-implanted pulmonary valves have raised concerns about higher than previously perceived occurrences of these events. We report on 2 patients who presented with right ventricular outflow tract obstruction secondary to prosthetic pulmonary valve endocarditis involving the valve's periphery, a rarely described and uncommon manifestation. One patient had an acute and rapidly deteriorating disease course, whereas the other had a more chronic and indolent course. Both patients were treated in the catheterization laboratory to relieve the obstructions, treatments which resulted in satisfactory acute results.

Developing tools to measure quality in congenital catheterization and interventions: the congenital cardiac catheterization project on outcomes (C3PO).

The broad range of relatively rare procedures performed in pediatric cardiac catheterization laboratories has made the standardization of care and risk assessment in the field statistically quite problematic. However, with the growing number of patients who undergo cardiac catheterization, it has become imperative that the cardiology community overcomes these challenges to study patient outcomes. The Congenital Cardiac Catheterization Project on Outcomes was able to develop benchmarks, tools for measurement, and risk adjustment methods while exploring procedural efficacy. Based on the success of these efforts, the collaborative is pursuing a follow-up project, the Congenital Cardiac Catheterization Project on Outcomes-Quality Improvement, aimed at improving the outcomes for all patients undergoing catheterization for congenital heart disease by reducing radiation exposure.