Abstract 15164: the Different Prognostic Values of T1 Mapping in Patients with Hypertrophic Cardiomyopathy

Objectives: This study aimed to determine the impact of T1 mapping on cardiovascular magnetic resonance (CMR) on long-term adverse outcomes in patients with hypertrophic cardiomyopathy (HCM). Background: In patients with HCM, the prognostic value of native T1 and extracellular volume fraction (ECV) for sudden cardiac death (SCD) has not been well defined. Methods: Consecutive 663 participants with HCM who underwent CMR were recruited. The follow-up endpoints included heart failure (HF)-related death and SCD or aborted SCD. Results: During the median follow-up time of 44 months (interquartile range [IQR]: 23 to 65.5 months), 55 (8.3%) participants reached the endpoint including 37 (5.6%) with SCD or aborted SCD and 18 (2.7%) with HF-related death. On Cox proportional hazards regression multivariable analyses, native T1 but not ECV was independently associated with CD (hazard ratio [HR]: 1.00; 95% confidence interval[CI] : 1.00 to 1.01; P = 0.02), while native T1 (HR: 1.01; 95%CI: 1.00 to 1.01; P = 0.008) and ECV (HR:1.15 for every 1% increase; 95%CI: 1.05 to 1.26; P = 0.003) were both independently associated with HF-related death after the adjustment for left ventricular ejection fraction (LVEF) and LV late gadolinium enhancement (LGE) extent. Conversely, native T1(HR: 1.00; 95% CI: 1.00 to 1.01; P = 0.40) and ECV (HR: 1.01; 95% CI: 0.94 to 1.08; P = 0.81) were not associated with SCD after the adjustment for non-sustained ventricular tachycardia, history of syncope and LV LGE extent. Conclusions: In this study of patients with HCM, T1 mapping had distinct prognostic associations; native T1 and ECV were both independently associated with HF-related death, whereas T1 mapping was not independently associated with SCD or aborted SCD. These findings may indicate distinct implications for the management of left ventricular fibrosis in HCM.