Risk stratification in patients with structurally normal hearts: Does fibrosis type matter?

Area of Science:

• Cardiovascular Imaging
• Cardiac Pathology
• Prognostic Biomarkers

Background:

• The clinical significance of myocardial abnormalities detected by cardiovascular magnetic resonance (CMR) in individuals with structurally normal hearts is not well understood.
• Nonischemic myocardial fibrosis (MF) is increasingly recognized in this population.

Purpose of the Study:

• To evaluate the prognostic value of nonischemic MF, assessed via late gadolinium enhancement (LGE) and extracellular volume fraction (ECV), in patients with structurally normal hearts.
• To determine the association of LGE and ECV with all-cause mortality, new-onset heart failure (HF), and arrhythmic outcomes.

Main Methods:

• A cohort of 525 patients with structurally normal hearts undergoing CMR was analyzed.
• Macroscopic MF was assessed using LGE, and diffuse MF using ECV derived from T1 mapping.
• Outcomes including all-cause mortality, new-onset HF, and arrhythmic events were tracked over a median follow-up of 5.8 years.

Main Results:

• Nonischemic LGE was found in 52.9% of patients, with no significant association with mortality or new-onset HF.
• An increase in ECV was significantly associated with all-cause mortality (HR per 1% increase: 1.19; p=0.009), even after multivariable adjustment (HR: 1.26; p=0.009).
• Neither LGE nor ECV showed a significant association with arrhythmic outcomes.

Conclusions:

• Nonischemic LGE is prevalent in patients with structurally normal hearts but does not predict adverse cardiovascular events.
• Elevated ECV is an independent predictor of all-cause mortality in this cohort.
• ECV quantification may serve as a valuable tool for risk stratification in patients with structurally normal hearts.