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OBJECTIVE The study sought to examine the prevalence and outcomes of sports participation (both competitive and recreational) in our single-center LQTS genotype positive pediatric population. BACKGROUND The risks of sports participation in patients with long QT syndrome (LQTS) are not clearly elucidated. METHODS A retrospective review was performed on genotype positive patients referred for the evaluation and management of LQTS between 1998 and 2013 at the Children’s Hospital of Philadelphia. Pediatric patients participating in competitive or recreational sports were included in the analysis and their charts were reviewed for documented LQTS events during follow-up. RESULTS The cohort of genotype-positive LQTS patients included 212 patients, and 103 patients (49%, female n = 53, average follow-up 7.1 ± 4.0 years, average QTc 468 ± 42 ms) participated in sports. A total of 105 LQTS disease-causing mutations were identified: KCNQ1 n = 60 (58%), KCNH2 n = 36 (35%), SCN5A n = 6 (6%), KCNE1 n = 1 (1%), and KCNE2 n = 2 (2%). All patients were treated with beta-blockade, with noncompliance in 1 patient and intolerance in 1 patient. Twenty-six patients participated in competitive sports (26%, female n = 15, average follow-up 6.9 ± 4.1 years, average QTc 461 ± 35 ms). Seventy-seven patients (75%, female n = 35, average follow-up 7.3 ± 3.9 years, average QTc 470 ± 43 ms) participated in recreational sports. No patients had LQTS symptoms during sports participation. Five appropriate implantable cardioverter-defibrillator shocks occurred in 2 patients, though none were related to sports participation. CONCLUSIONS In this series no cardiac events and no deaths were observed in treatment-compliant LQTS children while participating in sports in 755 patient-years of follow-up.

The characteristics of Ca2+ signaling in fura 2-loaded whole cell-clamped myocytes obtained from samples of human atrial appendages of 3-day to 4-yr-old patients were examined. In isolated myocytes, activation of Ca2+ current (ICa) (2.47 +/- 0.23 pA/pF) at 0 mV elicited sizable intracellular Ca2+ (Cai) transients (240 +/- 45 nM), which were caused by the release of Ca2+ from intracellular stores as they were suppressed in the presence of ryanodine or caffeine. The voltage dependence of both Cai transients and ICa were similar and bell shaped. The rate of release of Ca2+, normalized for the maximal Ca2+ release, increased with age, indicating increased efficiency of Ca2+ signaling in more mature myocytes. The results suggest that ICa-gated release of Ca2+ from the sarcoplasmic reticulum is the primary mechanism regulating the signaling of contraction in early postnatal as well as older human atrial myocytes.

OBJECTIVE-The study sought to examine the prevalence and outcomes of sports participation (both competitive and recreational) in our single-center LQTS genotype positive pediatric population. BACKGROUND-The risks of sports participation in patients with long QT syndrome (LQTS)are not clearly elucidated.

Background - Anesthesia strategies for pediatric ablation procedures include general anesthesia (GA) and monitored anesthesia care (MAC). The effects of anesthesia strategy on arrhythmia inducibility and procedural outcomes have not been investigated. Methods - A multicenter retrospective study was performed, utilizing data from the NCDR ® IMPACT Registry. Data from subjects 1-21 years undergoing elective first-time electrophysiology study (EPS) for evaluation of documented SVT, EAT, or PVC/VT from 4/1/16-12/31/19 were included, excluding cases with WPW, congenital heart disease, and/or cardiomyopathy. The primary outcome was a negative EPS, defined as failure to induce the clinical tachyarrhythmia. Secondary outcomes included ablation success and adverse events (AE). Results - 6621 subjects from 78 centers were evaluated: 49% male; mean age 13.3±3.8 years. GA was utilized in 5913 (89%), with MAC in 708 (11%). A negative EPS occurred in 9% of cases overall, with no difference by anesthesia strategy (9% GA vs. 10% MAC, p=0.2). In SVT and EAT, there was no significant difference in likelihood of a negative EPS by anesthesia strategy. In PVC/VT, there was a higher rate of negative EPS under GA (28% GA vs. 16% MAC, p=0.02), translating to a higher rate of non-ablation (34% GA vs. 14% MAC, p<0.001). In multivariable models, GA was associated with negative EPS in PVC/VT (OR 2.2, 95% CI 1.1-4.4, p=0.03), but not in SVT or EAT. Acute ablation success was not different between strategies (94% GA vs. 94% MAC, p=0.2). Major AE were rare, with no differences between GA and MAC. Conclusions - In this first report on pediatric ablation data in IMPACT, there were no differences between GA and MAC in SVT or EAT inducibility, acute ablation success, or major AE. GA was associated with higher rates of non-inducibility and non-ablation in PVC/VT cases. A MAC strategy should be considered for PVC/VT ablation in the pediatric population.

Congenital junctional ectopic tachycardia (JET) is a difficult to treat arrhythmia with a variably poor response to pharmacologic intervention. We report on the successful treatment of a 17-day-old infant with JET via transcatheter radiofrequency ablation of the arrhythmogenic focus resulting in resolution of the tachycardia and maintenance of normal atrioventricular nodal function. Transcatheter radiofrequency ablation techniques should be considered in infants with life-threatening arrhythmia recalcitrant to standard forms of drug therapy.

cardiac mapping, electrophysiology, three-dimensional systems, ventricular tachycardiaA 16-year-old female with a history of tachycardia-induced dilated cardiomyopathy (left ventricular ejection fraction 32%) underwent catheter ablation. Baseline electrocardiogram demonstrated ventricular tachycardia (VT) with a left bundle branch block pattern and an inferior axis (Fig. 1), which was likewise observed during electrophysiology study. Three-dimensional (3D) electroanatomic mapping was performed using the CARTO 3 System (Biosense Webster, Diamond Bar, CA, USA). Detailed mapping identified local electrograms preceding the ectopic QRS complex by 56 milliseconds and with a 12/12 lead pace-map match within the left coronary cusp. Selective left main coronary artery (LMCA) angiography was performed at

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