PO-03-125 VENTRICULAR PREEXCITATION AND PEDIATRIC HYPERTROPHIC CARDIOMYOPATHY: ETIOLOGY AND ACCESSORY PATHWAY CHARACTERISTICS

The etiology of pediatric hypertrophic cardiomyopathy (HCM) is varied. Ventricular preexcitation (VPe) well recognized, yet little known regarding the specific etiology, and accessory pathways (AP) characteristics. Define HCM in patients with VPe characteristics responsible APs. Retrospective cohort study <21 years age HCM/VPe from 2000-22. was defined as sarcomeric/non-sarcomeric (isolated HCM), storage disorder, metabolic disease, or genetic syndrome. AP were designated atrioventricular (AV) fasciculoventricular fibers (FVF) using standard invasive EP criteria when available. AV APs high risk if any following <250 ms: shortest preexcited RR interval AF, paced cycle length, APERP. ECG compared exclusively secondary to an FVF those anteroseptal AP-mediated VPe. From a total 345 HCM, 28 (8%) had proportion varied significantly between etiologic groups: isolated 10/220 (5%), 8/17 (47%), 5/19 (26%), syndrome 5/89 (6%), p < 0.001. Six (21%) clinical AF (1 SPPRI ms, 4 disease). Invasive performed 22, identifying 39 (23 AP, 16 FVF; fig 1). resulted 8 (36%) patients. Multiple seen plus 10 (45%). Five (23%) high-risk conduction properties (≥1 each group). Ablation acutely successful 13/14 recurrence 3. only complication single case heart block after ablation midseptal AP. Patients disease larger QRS amplitudes (median 42.3 v. 23.0 mm, 0.01). delta wave amplitude did not discriminate 4.3 4.1 = 0.92). multiple may be associated childhood HCM. This most common disorders important implications for prognosis management.