The Relationship between Symptom Burden and Myocardial Fibrosis in Patients with Hypertrophic Cardiomyopathy.

Background: Assessing the risk of sudden cardiac death in hypertrophic cardiomyopathy (HCM) patients is crucial. Cardiac magnetic resonance imaging (CMR) with late gadolinium enhancement (LGE) helps identify fibrosis, a key risk factor for sudden cardiac death. Current American Heart Association guidelines recommend implantable cardioverter-defibrillators for primary prevention in HCM patients with over 15% LGE. However, accurate LGE quantification requires specialized software, which is often unavailable in many centers. Symptom severity is often closely correlated with disease severity. This study investigates the relationship between symptom burden and high fibrosis in HCM patients. Methods: HCM patients from our cardiomyopathy clinic who underwent CMR between October 2021 and May 2023 were included. Symptom burden was assessed with the Kansas City Cardiomyopathy Questionnaire (KCCQ), with a lower score indicating higher symptom burden. High fibrosis was defined as LGE of 15% or more, evaluated by two radiologists. Results: Among 195 patients, 57 had high fibrosis. There were no significant differences in demographic data between groups. However, the high fibrosis group had significantly lower KCCQ scores, higher troponin and N-terminal pro B-type natriuretic peptide levels, lower left ventricular ejection fraction (LVEF), and greater wall thickness and LV mass index (LVMI). Logistic regression identified KCCQ score, LVEF derived from CMR, and CMR-LVMI as independent predictors of high fibrosis. A KCCQ score cut-off of 57.9 predicted high fibrosis with 77.1% sensitivity and 33.3% specificity (area under the curve: 0.717). Conclusions: Lower KCCQ score, reflecting higher symptom burden, was an independent predictor of high fibrosis in the enrolled HCM patients, highlighting its potential utility for fibrosis risk assessment.