Abstract 12149: Impact of Elevated Cardiac Troponin and Increased Fibrosis on Clinical Manifestations in Hypertrophic Cardiomyopathy

Abstract

Introduction: Recently, in patients with hypertrophic cardiomyopathy (HCM), an abnormal serum concentration of cardiac troponin (cTn), which is a sensitive marker of myocyte injury, was reported to be an independent predictor of the adverse outcome. In addition, late gadolinium-enhancement (LGE) cardiac magnetic resonance (CMR) imaging, which has been used to uniquely characterize the extent of myocardial fibrosis, has prognostic value in HCM. However, the relationship between myocyte injury, fibrosis, and clinical events/manifestations remains unclear. Hypothesis: A combined analysis using cTn and LGE by CMR may help to identify the clinical events/manifestations in patients with HCM. Methods: Eighty-seven HCM patients receiving regular outpatient treatment underwent CMR (cine and LGE imaging). LV myocardial fibrosis mass index (FMI) was quantified and the distribution/pattern of LGE was analyzed using 17 segment model. Serum cTnI was measured within a week around CMR testing. cTnI elevation was defined as ≥ 0.05ng/mL. Clinical events were defined as heart failure (HF) admission, ventricular tachycardia (VT), atrial fibrillation, and syncope. Results: In total patients, mean age was 65.7 ± 15.0 years old and female patients were 41.4%. HF and VT events were observed in 22 (25%) and 16 (18%) patients, respectively. Both elevated cTnI and higher FMI were associated with the combined clinical events (P<0.01 and P<0.05, respectively). Elevated cTnI was associated not with HF (P=0.06), but with VT (P<0.001). In contrast, higher FMI was associated with HF (P=0.01), but not with VT (P=0.67). A grouping according to both cTnI and FMI showed the good stratification for clinical events as shown in the figure. Conclusions: In HCM patients, both cTn and FMI were significant markers for clinical events in HCM patients. In particular, elevated cTn was strongly associated with VT. Combined analysis of cTn and CMR may be useful in clinical practice for HCM.