Diffuse Fibrosis in Hypertrophic Cardiomyopathy

JACC AdvPublished 28 Aug 2026

Authors' conclusion

Myocardial ECV was independently associated with long-term adverse outcomes. Multiparametric CMR assessment may improve risk stratification in HCM.

Study context

Population: Patients with hypertrophic cardiomyopathy (HCM) and preserved left ventricular (LV) ejection fraction (≥50%) who underwent cardiac magnetic resonance (CMR), including quantification of extracellular volume (ECV) and late gadolinium enhancement (LGE) burden, between 2012 and 2021consecutive patients with HCM and preserved LV ejection fraction
Participants: 1,050 patients

Exposure: Prognostic value of ECV beyond established clinical and imaging variables
Outcome: Composite of:
Mortality
Appropriate ICD therapy
Heart transplantation
Follow-up: Median 5.6 years (IQR: 2.5-7.8 years)

As reported in the abstract

Estimate (95% CI)P value

ECV ≥32% vs ECV <32%lower event-free survival with ECV ≥32%

adjusted HR 1.81(1.24–2.64)

P < 0.001

higher ECVmultivariable Cox regression; independently associated

HR 1.05 per 1% increase(1.02–1.09)

P = 0.001

older age vs ECV <32%multivariable Cox regression

HR 1.05(1.03–1.06)

P < 0.001

NYHA functional class ≥II vs ECV <32%multivariable Cox regression

HR 1.96(1.23–3.11)

P = 0.004

diabetes mellitus vs ECV <32%multivariable Cox regression

HR 1.89(1.27–2.81)

P = 0.002

Primary endpoint occurred: 124 patients (11.8%)
Deaths: 111 deaths (10.6%)
Appropriate implantable cardioverter-defibrillator (ICD) discharges: 12 appropriate ICD discharges (1.1%)
Heart transplantation: 1 heart transplantation (0.1%)

Observational data: associations, not effects.

Baseline characteristics

Diffuse Fibrosis in Hypertrophic Cardiomyopathy. JACC Adv. Published 28 August 2026. doi:10.1016/j.jacadv.2026.103224

Summarised from the published abstract; every number is checked against it