Abstract 14760: Myocardial Scarring by Magnetic Resonance Predicts Sudden Cardiac Death in Pediatric Patients With Hypertrophic Cardiomyopathy

Abstract

Introduction: Cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) has been shown to be an independent predictor of sudden cardiac death (SCD) in adults with hypertrophic cardiomyopathy (HCM). The clinical significance of LGE in pediatric HCM patients is unknown. Hypothesis: LGE improves the SCD risk prediction in children with HCM. Methods: We retrospectively analyzed the CMR images and reviewed the outcomes pediatric HCM patients. Results: Amongst the 720 patients from 30 centers, 73% were male, with a mean age of 14.2±4.8 years. During a mean follow up of 2.6±2.7 years (range 0-14.8 years), 34 experienced an episode of SCD or equivalent. LGE (Figure 1A) was present in 34%, with a mean burden of 14±21g, or 2.5±8.2g/m2 (6.2±7.7% of LV myocardium). The presence of ≥1 adult traditional risk factor (family history of SCD, syncope, LV thickness >30mm, non-sustained ventricular tachycardia on Holter) was associated with an increased risk of SCD (HR=4.6, p<0.0001). The HCM Risk-Kids score predicted SCD (p=0.002). The presence of LGE was strongly associated with an increased risk (HR=3.8, p=0.0003), even after adjusting for traditional risk factors (HR adj =3.2, p=0.003) or the HCM Risk-Kids score (HR adj =3.5, p=0.003). Furthermore, the burden of LGE was associated with increased risk (HR=2.1/10% LGE, p<0.0001). LGE burden remained independently associated with an increased risk for SCD after adjusting for traditional risk factors (HRadj=1.5/10% LGE, p=0.04) or HCM Risk-Kids (HRadj=1.9/10% LGE, p=0.0018, Figure 1B). The addition of LGE burden improved the predictive model using traditional risk markers (C statistic 0.67 vs 0.77, p=0.003) and HCM Risk-Kids (C statistic 0.68 vs 0.74, p=0.045). Conclusions: Quantitative LGE is an independent risk factor for SCD in pediatric patients with HCM and improves the performance of traditional risk markers and the HCM Risk-Kids Score for SCD risk stratification in this population.