Massieve LVH bij pediatrische HCM: vroeger diagnose, vaker sarcomere variant, drievoudig verhoogde sterfte

BACKGROUND: Massive left ventricular hypertrophy (LVH) is a risk factor for sudden cardiac death in children with hypertrophic cardiomyopathy (HCM), but little is understood about its natural history. METHODS: Patients with pediatric-onset HCM identified from two registries (SHaRe [Sarcomeric Human Cardiomyopathy Registry] and IPHCC [International Paediatric Hypertrophic Cardiomyopathy Consortium]) with or without massive LVH were compared. Massive LVH was defined as absolute maximal left ventricular wall thickness ≥30 mm or MLVWT z-score ≥+20 at age <18. Data from SHaRe and IPHCC include encounters from January 1960 through March 2024 and January 1970 through March 2024 respectively. Demographic, clinical, and serial MLVWT data were collected. RESULTS: 587 patients were identified (54 female [30%]; 186 with massive LVH). Children with massive LVH were diagnosed younger (median 9.2 years [IQR 2.1–13.1] vs 13.6 [9.7–15.5]; p<0.001), more often had sarcomeric variants (72% vs 61%; p=0.034), and showed higher HCM-related mortality (unadjusted HR 3.3; 95% CI 1.2–9.7; p=0.026). Major ventricular arrhythmia events and HF events were also significantly more frequent. CONCLUSIONS: Massive LVH in pediatric HCM is associated with earlier diagnosis, more sarcomeric variants, and a markedly worse prognosis — supporting earlier intervention and more intensive surveillance in this subgroup.