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The safety and utility of the Advisor™ High-Density Grid mapping catheter (HDGC) in children and congenital heart disease (CHD) patients are not well described.A single-center retrospective cohort study of pediatric and CHD patients undergoing electrophysiology study and ablation to determine the effect of HDGC use on outcomes including complications, fluoroscopy use, procedure duration, acute ablation success, and arrhythmia recurrence.HDGC was used in 74/261 (28.3%) cases. HDGC subjects differed by median age (17 vs. 13 years; p 0.001), weight (68 vs. 50 kg; p 0.001), and prevalence of significant CHD (42% vs. 3%; p 0.001). Arrhythmia substrates were dissimilar: HGDC cases had higher frequencies of intra-atrial re-entrant tachycardia (25.7% vs. 0.5%), atrial flutter (8.1% vs. 1.1%), ectopic atrial tachycardia (13.5% vs. 3.7%), and premature ventricular contractions (9.5% vs. 0.5%), and lower incidences of atrioventricular re-entrant tachycardia (16.2% vs. 46.1%). Complications were rare (n = 5, 1.9%) with no significant difference between groups (p = 1.00). Procedure duration-but not fluoroscopy exposure-was significantly longer in HDGC cases (median 256 vs. 216 min, p 0.001). Acute success was lower (93.2% vs. 99.4%; p = 0.01) and recurrences higher (13.2% vs. 3.8%; p = 0.016) in HDGC compared to non-HDGC cases.HDGC use in children and CHD patients is safe and not associated with higher complication rates. The lower acute success and higher recurrence rates in HDGC cases likely reflect a bias toward HDGC use in more complex arrhythmia substrates rather than less favorable ablation outcomes.

Background: Insight into type 5 long QT syndrome (LQT5) has been limited to case reports and small family series. Improved understanding of the clinical phenotype and genetic features associated with rare KCNE1 variants implicated in LQT5 was sought through an international multicenter collaboration. Methods: Patients with either presumed autosomal dominant LQT5 (N = 229) or the recessive Type 2 Jervell and Lange-Nielsen syndrome (N = 19) were enrolled from 22 genetic arrhythmia clinics and 4 registries from 9 countries. KCNE1 variants were evaluated for ECG penetrance (defined as QTc >460 ms on presenting ECG) and genotype-phenotype segregation. Multivariable Cox regression was used to compare the associations between clinical and genetic variables with a composite primary outcome of definite arrhythmic events, including appropriate implantable cardioverter-defibrillator shocks, aborted cardiac arrest, and sudden cardiac death. Results: A total of 32 distinct KCNE1 rare variants were identified in 89 probands and 140 genotype positive family members with presumed LQT5 and an additional 19 Type 2 Jervell and Lange-Nielsen syndrome patients. Among presumed LQT5 patients, the mean QTc on presenting ECG was significantly longer in probands (476.9±38.6 ms) compared with genotype positive family members (441.8±30.9 ms, P P =0.001). Event incidence did not differ significantly for Type 2 Jervell and Lange-Nielsen syndrome patients relative to the overall heterozygous cohort (10.5% [2/19]; HR 1.7 [95% CI, 0.3–10.8], P =0.590). The cumulative prevalence of the 32 KCNE1 variants in the Genome Aggregation Database, which is a human database of exome and genome sequencing data from now over 140 000 individuals, was 238-fold greater than the anticipated prevalence of all LQT5 combined (0.238% vs 0.001%). Conclusions: The present study suggests that putative/confirmed loss-of-function KCNE1 variants predispose to QT prolongation, however, the low ECG penetrance observed suggests they do not manifest clinically in the majority of individuals, aligning with the mild phenotype observed for Type 2 Jervell and Lange-Nielsen syndrome patients.

OBJECTIVES: The aim of this paper was to investigate whether ventricular arrhythmias in children with catecholaminergic polymorphic ventricular tachycardia (CPVT) show circadian patterns. BACKGROUND: Circadian arrhythmic patterns have been established in long QT, Brugada, and early repolarization, but have not been investigated in CPVT. METHODS: This is a multicenter, retrospective review of pediatric CPVT patients, age

BACKGROUND Interventional cardiac catheterization (cath) and electrophysiology (EP) procedures are not routinely performed together. There are several perceived barriers affecting this practice, though there are also advantages for both the patient and practitioner to a combined approach. METHODS This was a single-center retrospective study reviewing combined cath and EP procedures with a preprocedural intention to intervene at Texas Children's Hospital from 2001 to 2014. We excluded procedures in which the intended procedure was purely diagnostic in nature. RESULTS A total of 121 patients requiring 125 procedures were identified, of which 61 patients underwent 62 procedures that met our inclusion criteria. Potential subgroups of interest included adult congenital heart disease patients (26% of cohort), single ventricle anatomy (34%), and heterotaxy (19%) and collectively 58% of procedures involved a patient in one of these groups. The combined nature of the procedure did not preclude a cath or EP intervention in any patient. There were no mortalities. There were three adverse events, affecting 4.8% of procedures. CONCLUSIONS Combined interventional cardiac cath and EP procedures in pediatric patients and those with congenital heart disease can be performed safely in a high-volume center. These combined procedures save patients the risk and inconvenience of multiple procedures, and further investigation into cost savings is warranted.

Current estimates of the incidence of tachyarrhythmias in infants rely on clinical documentation and may not reflect the true rate in the general population. Our aim was to describe the epidemiology of tachyarrhythmia detected in a large cohort of infants using direct-to-consumer heart rate (HR) monitoring.Data were collected from Owlet Smart Sock devices used in infants in the US with birthdates between February 2017 and February 2019. We queried the HR data for episodes of tachyarrhythmia (HR of ≥240 bpm for60 seconds).The study included 100 949 infants (50.8% male) monitored for more than 200 million total hours. We identified 5070 episodes of tachyarrhythmia in 2508 infants. The cumulative incidence of tachyarrhythmia in our cohort was 2.5% over the first year of life. The median age at the time of the first episode of tachyarrhythmia was 36 days (range, 1-358 days). Tachyarrhythmia was more common in infants with congenital heart disease (4.0% vs 2.4%; P = .015) and in females (2.7% vs 2.0%; P .001). The median length of an episode was 7.3 minutes (range, 60 seconds to 5.4 hours) and the probability of an episode lasting longer than 45 minutes was 16.8% (95% CI, 15.4%-18.3%).We found the cumulative incidence of tachyarrhythmia among infants using direct-to-consumer HR monitors to be higher than previously reported in studies relying on clinical diagnosis. This finding may represent previously undetected subclinical disease in young infants, the significance of which remains uncertain. Clinicians should be prepared to discuss these events with parents.

Background Arrhythmias are common in the pediatric population. In patients unable to take oral medications or in need of acute therapy, options of intravenous (IV) antiarrhythmic medications are limited. Recently IV sotalol has become readily available, but experience in children is limited. Objective The purpose of this study was to describe our initial experience with the use of IV sotalol in the pediatric population. Methods A retrospective study of all pediatric patients receiving IV sotalol was performed. Patient demographic characteristics, presence of congenital heart disease, arrhythmia type, efficacy of IV sotalol use, and adverse effects were evaluated. Results A total of 47 patients (26 (55%) male and 24 (51%) with congenital heart disease) received IV sotalol at a median age of 2.05 years (interquartile range 0.07–10.03 years) and a median weight of 12.8 kg (interquartile range 3.8–34.2 kg), and 13 (28%) received IV sotalol in the acute postoperative setting. Supraventricular arrhythmias occurred in 40 patients (85%) and ventricular tachycardia in 7 (15%). Among 24 patients receiving IV sotalol for an active arrhythmia, acute termination was achieved in 21 (88%). Twenty-three patients received IV sotalol as maintenance therapy for recurrent arrhythmias owing to inability to take oral antiarrhythmic medications; 19 (83%) were controlled with sotalol monotherapy. No patient required discontinuation of IV sotalol secondary to adverse effects, proarrhythmia, or QT prolongation. Conclusion IV sotalol is an effective antiarrhythmic option for pediatric patients and may be an excellent agent for acute termination of active arrhythmias. It was well tolerated, with no patient requiring discontinuation secondary to adverse effects.

We present a new technique for driveline insertion of the HeartWare ventricular assist device (HVAD) designed to preserve the integrity of the abdominal wall structure. Because of the size of the HVAD driveline connector (12 mm in diameter: triple the size of the driveline cable), the standard tunneling maneuver can result in tearing of the abdominal wall muscle layer, which is a primary mechanism to prevent ascending driveline infection. We find that our technique is particularly useful in children because their abdominal wall muscles are more fragile and thereby prone to accidental injury with blunt penetration when the standard technique is used.

Interventional cardiac catheterization (cath) and electrophysiology (EP) procedures are not routinely performed together. There are several perceived barriers affecting this practice, though there are also advantages for both the patient and practitioner to a combined approach.This was a single-center retrospective study reviewing combined cath and EP procedures with a preprocedural intention to intervene at Texas Children's Hospital from 2001 to 2014. We excluded procedures in which the intended procedure was purely diagnostic in nature.A total of 121 patients requiring 125 procedures were identified, of which 61 patients underwent 62 procedures that met our inclusion criteria. Potential subgroups of interest included adult congenital heart disease patients (26% of cohort), single ventricle anatomy (34%), and heterotaxy (19%) and collectively 58% of procedures involved a patient in one of these groups. The combined nature of the procedure did not preclude a cath or EP intervention in any patient. There were no mortalities. There were three adverse events, affecting 4.8% of procedures.Combined interventional cardiac cath and EP procedures in pediatric patients and those with congenital heart disease can be performed safely in a high-volume center. These combined procedures save patients the risk and inconvenience of multiple procedures, and further investigation into cost savings is warranted.

The function of chemokine receptors on structural cells is only partially known. We previously reported the expression of a functional CCR3 receptor on airway epithelial cells (EC). We speculated that CCR3 might drive wound repair and expression of inflammatory genes in epithelium. The human airway EC lines BEAS-2B, 16-HBE, and primary bronchial EC were used to test the effect of in vitro challenge with the CCR3 ligands CCL11/eotaxin, CCL24/eotaxin-2, or CCL26/eotaxin-3 on 1) wound repair, using an established wound model; 2) cell proliferation and chemotaxis, using specific fluorometric assays; and 3) gene expression, using pathway-specific arrays for inflammatory and profibrotic cytokines, chemokines, and chemokine receptor genes. Agonist specificity was tested by cell pretreatment with an AstraZeneca CCR3 antagonist (10−8 – 10−6 M). CCL24 challenge significantly accelerated epithelial wound closure, with similar effects exerted by CCL11 and CCL26. This effect was time dependent, submaximal at 1 nM, and comparable in potency to epidermal growth factor. CCL24 induced a concentration-dependent increase in EC proliferation and chemotaxis, with significant effects observed at 10 nM. The AstraZeneca compound selectively inhibited these CCL24-mediated responses. CCL11 induced the up-regulation of several profibrogenic molecules such as fibroblast growth factor 1 and 5 and of several CC and CXC chemokines. Epithelial immunostaining for CCR3 was stronger in bronchial biopsies of asthmatics displaying marked inflammatory changes than in nondiseased samples. Epithelial CCR3 participates in key functions for wound repair, amplifies the expression of profibrogenic and chemokine transcripts, and appears up-regulated in inflamed asthmatic airways.