Three-Dimensional Strain for Assessing Myocardial Fibrosis in Hypertrophic Cardiomyopathy

Background: Two-dimensional (2D) speckle-tracking echocardiography (STE) for fibrosis detection has been validated against cardiac magnetic resonance late gadolinium enhancement (CMR-LGE) in hypertrophic cardiomyopathy (HCM), whereas 3-dimensional speckle-tracking echocardiography (3D-STE) may overcome limitations of 2D imaging. Objectives: The authors aimed to evaluate whether 3D-STE can quantify replacement fibrosis as a surrogate for CMR-LGE. Methods: Two-dimensional speckle-tracking echocardiography, 3D-STE, and the extent of late gadolinium enhancement (%LGE) were prospectively measured in patients with HCM within ≤72 hours. Results: Among 511 patients with HCM (age 49.0 ± 14.3 years; men 340/511, 66.5%), strain parameters were significantly lower in patients with HCM and LGE [LGE (+)] than those in patients without LGE [LGE (-)]. Three-dimensional global longitudinal strain (GLS-3D) correlated moderately with GLS-2D (r = 0.622; 95% CI: 0.565-0.672; P < 0.001) and most strongly with %LGE (r = -0.698; 95% CI: -0.741 to -0.649; P < 0.001). A quadratic model explained the relationship between GLS-3D and %LGE better than the linear model (R2 = 0.448 vs 0.381). GLS-3D was independently associated with extensive LGE (%LGE ≥15%) (OR = 0.629; 95% CI: 0.553-0.716; P < 0.001), and showed the highest AUC for detecting extensive LGE (AUC = 0.894; 95% CI: 0.854-0.934; P < 0.001). At a cutoff value of 15.25%, GLS-3D yielded 87.3% sensitivity (95% CI: 75.5%-94.7%) and 78.3% specificity (95% CI: 74.4-82.2%). Conclusions: GLS-3D showed the strongest correlation with %LGE among strain parameters and may serve as a surrogate marker for CMR-LGE in HCM.