Incremental value of myocardial global longitudinal strain in predicting major adverse cardiac events among patients with hypertrophic cardiomyopathy

Abstract Objectives Endocardial global longitudinal strain (endo‐GLS) measured with echocardiography (echo) has been demonstrated to be associated with myocardial fibrosis (MF) and is a prognostic predictor in patients with hypertrophic cardiomyopathy (HCM). Late gadolinium enhancement cardiac magnetic resonance (LGE‐CMR) imaging showed that MF is primarily located in the myocardial layer of the extremely hypertrophic septal or ventricular wall. We hypothesized that GLS of the myocardial layer (myo‐GLS) is more strongly correlated with the extent of LGE (%LGE) and is a more powerful prognostic factor than endo‐GLS. Methods A total of 177 inpatients (54.0 IQR: 43.0, 64.0 years, female 37.3%) with HCM were retrospectively included from May 2019 to April 2021. Among them, 162 patients underwent echocardiographic examination and contrast‐enhanced CMR within 7 days. Myo‐GLS and %LGE were blindly assessed in a core laboratory. All the patients were followed after they were discharged. Results During a mean follow‐up of 33.77 IQR 30.05, 35.40 months, 14 participants (7.91%) experienced major adverse cardiac events (MACE). The MACE (+) group showed lower absolute endo‐GLS and myo‐GLS than the MACE (‐) group. Myo‐GLS was more associated with %LGE ( r = ‐.68, P < .001) than endo‐GLS ( r = ‐.64, P < .001). Cox multivariable analysis indicated that absolute myo‐GLS was independently associated with MACE (adjusted hazard ratio = .75, P < .05). Myo‐GLS was better than endo‐GLS at detecting MACE (+) patients (‐8.64%, AUC .939 vs. ‐ 16.375%, AUC .898, P < .05). Conclusions Myo‐GLS is a stronger predictor of MACE than endo‐GLS in patients with HCM and is highly correlated with %LGE.