CONGRESS ABSTRACT

Background: Late gadolinium enhancement (LGE) is an important prognostic marker in patients with Hypertrophic cardiomyopathy (HCM) and when its extent is >15% it is associated with high risk of sudden cardiac death (SCD). Aim: We proposed a novel method of Cardiac Magnetic Resonance (CMR), the LGE- dispersion mapping, to assess heterogeneity of scar (signal heterogeneity in scar), and evaluated its clinic and prognostic role in patients with HCM. Methods: 183 patients with HCM and a low- or intermediate 5-year risk of SDC underwent CMR with LGE. From LGE images a parametric map was generated with the identification of non-enhanced, mildly-enhanced and hyper-enhanced myocardium. For each pixel of these maps a score from 0 to 8 was assigned, where 0 was assigned when all the 8 surrounding pixels had the same quality (non-enhancement, mild-enhancement or hyper-enhancement) of the central pixel, and 8 when all the surrounding pixels had different quality of the central pixel. The Global dispersion score (GDS) was calculated as the average score of all the pixels of the images. Results: During a follow-up time of 6 years (25th-75th 4-10), 22 patients had hard cardiac events (SDC, appropriate implantable cardioverter defibrillator therapy, resuscitated cardiac arrest and sustained ventricular tachycardia). Kaplan Meier analysis showed that patients with High-GDS had worse prognosis than those low-GDS (p<0.0001). GDS>0.86 was the only independent predictor of cardiac events (HR 9.9, 95% CI 2.9-34.6, p=0.0003). When compared to LGE extent >15%, High-GDS permitted to improve classification of risk of these patients (NRI 0.39, CI 95% 0.11-0.72, p<0.019). Conclusions: LGE-dispersion mapping is a marker of scar heterogeneity and provides a better risk stratification than LGE presence and extent in patients with HCM and a low- intermediate 5-year risk of SCD