The Role of Echocardiography in the Assessment of Epicardial Adipose Tissue: A Systematic Review and Meta-analysis

Epicardial adipose tissue (EAT) is a metabolically active visceral fat depot implicated in cardiometabolic and cardiovascular (CV) disease. Although cardiac magnetic resonance (CMR) and cardiac computed tomography (cCT) enable accurate volumetric quantification of EAT, their cost, limited availability, and-particularly for cCT-radiation exposure, restrict their use in preventive and longitudinal settings. Transthoracic echocardiography (TTE) is widely accessible and radiation-free, but its validity as a surrogate of volumetric EAT assessment and its broader clinical role remain incompletely defined.

To systematically synthesize disease-specific evidence linking TTE-derived EAT thickness with major CV phenotypes and to quantitatively assess its association with volumetric EAT measured by CMR or cCT.

A systematic search of PubMed and PubMed Central (January 2000-December 2025) identified adult studies evaluating associations between TTE-derived EAT thickness and coronary artery disease (CAD), atrial fibrillation (AF), or heart failure with preserved ejection fraction (HFpEF), and correlations between TTE-derived EAT thickness and CMR- or cCT-derived EAT volume. Correlation coefficients were pooled using a random-effects model after Fisher's z-transformation. An exploratory meta-analysis assessed associations with major adverse cardiovascular events (MACE).

Seventeen disease-specific studies consistently demonstrated associations between increased TTE-derived EAT thickness and CAD severity, AF burden and recurrence, and adverse HFpEF phenotypes. Five validation studies were included; four comparing TTE with CMR were pooled, yielding a moderate-to-strong correlation (r = 0.77, 95% CI 0.65-0.93; p < 0.01; I² = 92.9%). Several studies reported associations between TTE- EAT thickness and cCT-derived EAT parameters. However, only one cCT study met our predefined criteria for inclusion in the quantitative validation analysis, whereas the remaining cCT studies were retained in the qualitative synthesis because of substantial methodological heterogeneity in cCT acquisition, segmentation approaches, and outcome definitions. Exploratory prognostic analysis suggested a directional association between increased TTE-derived EAT thickness and MACE.

TTE-derived EAT thickness correlates with volumetric EAT and is consistently associated with major CV phenotypes. Standardization and prospective outcome-driven validation are required before routine clinical implementation.