Abstract
BACKGROUND: Sarcopenia affects 16–57% of patients with heart failure (HF) and worsens prognosis. Current assessments relying on muscle mass and strength are confounded by fluid retention and cannot detect early qualitative changes. Skeletal muscle passive stiffness is primarily determined by titin and extracellular matrix components, which undergo pathological alterations in HF with potentially distinct mechanisms across phenotypes. These abnormalities may remain undetected at rest but become apparent under passive stretch conditions. The VISMARC-HF (Viscoelastic evaluation with Shear wave elastography for Muscle Abnormality and Regional Composition in patients with Heart Failure) study aims to assess the clinical utility of shear wave elastography (SWE) for evaluating skeletal muscle in older patients with HF, test whether SWE-derived parameters are associated with clinical outcomes, and explore whether distinct viscoelastic phenotypes exist across the HF spectrum. METHODS: This prospective, single-center observational cohort study will enroll 625 consecutive patients with HF aged ≥ 65 years who can ambulate independently at discharge from university hospital. Participants undergo SWE assessment of rectus femoris and biceps brachii under both relaxed and passive stretch conditions, body composition analysis by dual-energy X-ray absorptiometry and bioelectrical impedance analysis, and sarcopenia evaluation according to the Asian Working Group for Sarcopenia 2025 criteria. Follow-up assessments are performed at 1 year, with outcome surveillance continuing through 2 years. The primary endpoint is all-cause mortality within 2 years. Secondary endpoints include composite cardiovascular events, physical performance measures, and changes in sarcopenia status. Cox proportional hazards analysis will assess associations between SWE parameters and outcomes, adjusting for the Meta-analysis Global Group in Chronic Heart Failure (MAGGIC) risk score and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels. DISCUSSION: By characterizing skeletal muscle viscoelastic properties under both relaxed and stretched conditions across the HF spectrum, the VISMARC-HF study addresses molecular-level abnormalities potentially missed by conventional assessment. Findings may provide foundational evidence for individualized approaches to muscle quality assessment in older patients with HF. TRIAL REGISTRATION: UMIN000057756 (Registered July 1, 2025). GRAPHICAL ABSTRACT: Prognostic value of skeletal muscle viscoelasticity in heart failure: overview of the VISMARC-HF study This visual abstract summarizes the study design and objectives of the VISMARC-HF study. This prospective cohort study aims to evaluate the clinical utility and prognostic value of skeletal muscle viscoelasticity in 625 older patients with heart failure (HF). The primary objective is to determine if muscle quality assessment using shear wave elastography (SWE) can predict clinical outcomes independent of conventional measures. The study protocol includes comprehensive baseline assessments at hospital discharge, including SWE of the rectus femoris and biceps brachii under both relaxed and passive stretch conditions. Sarcopenia is diagnosed according to the AWGS 2025 consensus criteria. Participants will undergo follow-up assessments at 1 year, with outcome surveillance continuing for 2 years. The primary endpoint is 2-year all-cause mortality. Secondary endpoints include HF hospitalization, composite cardiovascular events, and changes in sarcopenia status. This study may provide foundational evidence for individualized muscle quality assessment in patients with HF. [Image: see text] SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12877-026-07016-6.