Background Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an uncommon, potentially lethal, ion channelopathy. Standard therapies have high failure rates and little is known about treatment in children. Newer options such as flecainide and left cardiac sympathetic denervation (LCSD) are not well validated. We sought to define treatment outcomes in children with CPVT. Methods and Results This is a Pediatric and Congenital Electrophysiology Society (PACES) multicenter, retrospective cohort study of CPVT patients diagnosed before 19 years of age. The cohort included 226 patients, including 170 probands and 56 relatives. Symptomatic presentation was reported in 176 (78%). Symptom onset occurred at 10.8 (IQR 6.8–13.2) years with a delay to diagnosis of 0.5 (0–2.6) years. Syncope (p<0.001), cardiac arrest (p<0.001) and treatment failure (p=0.008) occurred more often in probands. Beta-blockers were prescribed in 205 of 211 patients (97%) on medication, and 25% experienced at least one treatment failure event. Implantable cardioverter defibrillators (ICDs) were placed in 121 (54%) and was associated with electrical storm in 22 (18%). Flecainide was used in 24% and LCSD in 8%. Six deaths (3%) occurred during a cumulative follow-up of 788 patient-years. Conclusions This study demonstrates a malignant phenotype and lengthy delay to diagnosis in CPVT. Probands were typically severely affected. Beta-blockers were almost universally initiated; however, treatment failure, non-compliance and sub-therapeutic dosing were often reported. ICDs were common despite numerous device-related complications. Treatment failure was rare in the quarter of patients on flecainide. LCSD was not uncommon although the indication was variable.

Patients with nonpost-operative JET have a wide range of clinical presentations, with younger patients demonstrating higher morbidity and mortality. With current medical, ablative, and device therapies, the majority of patients have a good clinical outcome.

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This large, multicentre study identifies contemporary challenges related to the diagnosis and prognostication of CPVT patients. Structural modelling of RyR2 can improve our understanding severe CPVT phenotypes. Wakeful rest, rather than exertion, often precipitated life-threatening cardiac events.

Smaller patients in general weigh less than approximately 15 kg, and larger patients weigh more than approximately 15 kg. þ The precise definition of "medical therapy that is either not effective or associated with intolerable adverse effects" is left up to the practitioner and family to decide. In general, however, the threshold for ineffectiveness and intolerability should be higher in smaller patients. For example, failure or

The clinical course and outcomes of pediatric patients with fascicular VT and nonfascicular LV VT are varied. Catheter ablation procedures can be curative.

Transvenous lead systems implanted in young children have a similar incidence of venous occlusion compared to older patients. Furthermore, patient age, body size, and lead characteristics at implant do not clearly predict venous occlusion.

Background Iron cardiomyopathy is a leading cause of death in transfusion dependent thalassemia major (TM) patients and MRI (T2*) can recognize preclinical cardiac iron overload, but, is unavailable to many centers. Design and Methods We evaluated the ability of 12-lead electrocardiography to predict cardiac iron loading in TM. 12-lead electrocardiogram and cardiac T2* measurements were performed prospectively, with a detectable cardiac iron cutoff of T2*less than 20 ms. Patients with and without cardiac iron were compared using two-sample statistics and against population norms using age and gender-matched Z-scores. Results 45/78 patients had detectable cardiac iron. Patients having cardiac iron were older and more likely female but had comparable liver iron burdens and serum ferritin. Increased heart rate (HR) and prolonged corrected QT interval (QTc) were present, regardless of cardiac iron status. Repolarization abnormalities were the strongest predictors of cardiac iron, including QT/QTc prolongation, left shift of T-wave axis, and interpretation of ST/T-wave morphology. Recursive partitioning of the data for females using T-axis and HR and for males using QT, HR and T-axis produced algorithms with AUROC’s of 88.3 and 87.1 respectively. Conclusions Bradycardia and repolarization abnormalities on 12-lead electrocardiography were the most specific markers for cardiac iron in thalassemia major. Changes in these variables may be helpful to stratify cardiac risk when cardiac MRI is unavailable. However, diagnostic algorithms need to be vetted on larger and more diverse patient populations and longitudinal studies are necessary to determine reversibility of the observed abnormalities.