PO-05-192 LOCAL HETEROGENEITY OF LATE GADOLINIUM ENHANCEMENT PREDICTS VENTRICULAR ARRHYTHMIA IN HYPERTROPHIC CARDIOMYOPATHY

Hypertrophic cardiomyopathy (HCM) is the most common cause of sudden cardiac death in young people. Despite recent advances in risk stratification using cardiac magnetic resonance (CMR) imaging, risk prediction remains suboptimal. Improved risk stratification is therefore warranted. Whether local heterogeneity of Late Gadolinium Enhancement (LGE) signal is associated with ventricular arrhythmia remains unknown. To determine whether local heterogeneity of LGE signal on CMR predicts ventricular arrhythmia and appropriate shocks after implantable cardioverter defibrillator (ICD) implantation in patients with HCM. Local heterogeneity was quantified by LGE-CMR signal dispersion score and compared with cardiovascular outcomes in 179 HCM patients who underwent ICD implantation. The primary outcome was appropriate ICD shocks. During a median follow-up time of 7.3 years the event rate was 0.015 per person year. History of ventricular arrhythmia (HR 9.413, p<0.001) and sudden cardiac death (HR 13.82, p<0.001) were associated with receiving an appropriate ICD shock in both univariable and multivariable analyses. History of syncope, family history of sudden cardiac death, non-sustained ventricular tachycardia, left ventricular wall thickness and presence of LGE were not associated with the primary outcome. When compared to patients without ICD shock, patients who received ICD shocks had higher burden of LGE gray zone (16.8±7.5% vs 25.8±3.5% p<0.001) and scar (10.5±6.7% vs 18.7±4.3% p<0.001) on CMR. Importantly, patients with ICD shocks had a higher dispersion score (1.20 vs 0.97, respectively), signifying higher degree of LGE signal heterogeneity (p=0.047). Dispersion score, a marker of local LGE signal heterogeneity of scar and gray zone was associated with a higher burden of ICD shocks in HCM patients who received ICDs. Mechanistically, local LGE signal heterogeneity could represent complex scar. These results may contribute to improved risk stratification for ventricular arrhythmia in HCM patients.