Abstract / Summary
Latent obstructive HCM (Latent-HCM) is challenging to detect at rest, yet carries a prognosis comparable to overt obstruction. This study evaluated the utility of CMR-FT-derived strain and tissue characterization parameters in identifying Latent-HCM in HCM patients, and constructed a multiparametric model to detect a myocardial phenotype associated with provocable LVOT obstruction. We initially assessed 159 consecutive patients with HCM who underwent CMR between September 2024 and December 2025. After excluding 31 patients with uncontrolled hypertension, infiltrative cardiomyopathy, persistent atrial fibrillation, coronary artery disease, or resting obstructive HCM, 128 patients were preliminarily enrolled. A further 16 patients were excluded due to poor CMR image quality ( n = 8) or lack of essential clinical data ( n = 8), leaving 112 patients in the final analysis (81 hypertrophic non-obstructive cardiomyopathy [HNOCM] and 31 Latent-HCM). All patients underwent 3.0 T CMR (cine, T1 mapping, late gadolinium enhancement [LGE]) and CMR-FT strain analysis. Global radial strain (GRS), global circumferential strain (GCS), global longitudinal strain (GLS), longitudinal time-to-peak strain (TTP-LS), strain rates, and extracellular volume fraction (ECV) were measured. Univariate and multivariate logistic regression were used to identify independent predictors, and receiver operating characteristic (ROC) curves were constructed to assess diagnostic performance. Compared with HNOCM group, the Latent-HCM group showed significantly higher left ventricular ejection fraction (LVEF), increased GRS and absolute GCS, prolonged TTP-LS, and lower ECV (all P < 0.05). Multivariate analysis identified GRS, TTP-LS, and ECV as independent predictors. The three-parameter combined model achieved an area under the ROC curve (AUC) of 0.888 (95% CI: 0.814–0.940), with a sensitivity of 83.87% and specificity of 88.89%, significantly outperforming any single parameter (DeLong test P < 0.05). CMR-FT-derived myocardial strain parameters (GRS, GCS) and ECV are associated with provocable LVOT obstruction and may help identify HCM patients who warrant further hemodynamic evaluation. The combined model integrating GRS, TTP-LS, and ECV provides promising performance in identifying a myocardial phenotype associated with provocable obstruction. However, this model should not be viewed as a replacement for provocative echocardiography; rather, it may serve as a non-invasive screening tool to help identify patients who warrant further hemodynamic evaluation. External validation is required before clinical application.