Abstract 4187: Identification of Late Gadolinium Enhancement by Contrast-Enhanced Magnetic Resonance Imaging as a Major Risk Factor for Sudden Death in Hypertrophic Cardiomyopathy
Background: Myocardial late gadolinium enhancement (LGE) on Contrast-Enhanced Magnetic Resonance Imaging (CE-MRI) of patients (pts) with hypertrophic cardiomyopathy (HCM) may indicate intra-myocardial fibrosis. We explored whether the presence and extent of LGE on CE-MRI among pts with HCM predicted ventricular arrhythmogenicity, and decreased survival.
Methods: 424 HCM pts [age = 55 ± 16 years (range 2 – 90), 41% females], without prior history of septal ablation/myectomy, underwent CE-MRI (GE 1.5T) during a 6-year period. We compared the presence and amount of LGE with degree of ventricular ectopy on Holter ECG (available in 220 pts) recorded during the same time period of the CE-MRI. All cause death and appropriate, VF-terminating ICD therapies were then recorded during a mean follow-up of 34 ± 14 months (range 7 – 85).
Results: 239 pts (56%) had LGE ranging from 0.4 – 65% of the myocardium. LGE -positive pts were more likely to have non-sustained ventricular tachycardia on Holter ECG [34/126 (27%) vs 8/94 (8.5%), p < 0.001], and had more total ventricular extrasystoles/24 hours (700 ± 2080 vs 103 ± 460, p < 0.001). During follow-up, 7 pts died and 4 received appropriate ICD discharges (9.7% of 41 pts with ICD). All 11 pts were LGE-positive. Event free survival was excellent (100%) in pts without LGE, and lower (95.4%) in pts with LGE (log rank, p < 0.002). Multivariate analysis (adjusting for age, gender, morphologic and functional data, and comorbidities) identified LGE involving ≥ 5% of LV mass (p=0.03, present in 7/11 pts with events), septal thickness≥30mm (p=0.03), and atrial fibrillation (p=0.02) as independent predictors of death or appropriate ICD discharges.
Conclusions: In pts with HCM, LGE by CE-MRI was strongly associated with surrogates of arrhythmia and was independently associated with subsequent death and/or ICD discharge. If replicated, LGE may be considered a major risk for sudden death in HCM.