Extracellular volume in the heart reflects disease severity and predicts outcomes. Data presented at the European Society of Cardiology Congress 2025 examined its value in 1,525 adults undergoing cardiovascular magnetic resonance imaging.

Both conventional extracellular volume and an indexed version adjusted for left ventricular mass and body surface area were measured. During a median follow-up of 52 months, 414 participants experienced heart failure hospitalization or death. Event-free survival declined across higher tertiles for both measures. Multivariate analysis adjusting for age, sex, left ventricular function, and N-terminal pro B-type natriuretic peptide confirmed that both conventional and indexed extracellular volume independently predicted adverse outcomes.

Conventional extracellular volume also correlated with aortic valve velocity, while the indexed version did not. Although indexed extracellular volume is more complex to calculate, it did not add prognostic value over the conventional method. These findings suggest that conventional extracellular volume remains a reliable and practical marker for risk stratification in patients with heart disease.

These findings indicate that conventional extracellular volume provides strong prognostic insight without the added complexity of indexed calculations.