Echocardiographic Global Longitudinal Strain and Myocardial Fibrosis in Patients with Left Ventricular Hypertrophy and Hypertrophic Cardiomyopathy.

Background: Myocardial fibrosis is an important pathological feature of hypertrophic cardiomyopathy (HCM) and is associated with ventricular arrhythmias, disease progression, and adverse clinical outcomes. Cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) is the reference non-invasive technique for myocardial fibrosis assessment; however, its availability may be limited. Global longitudinal strain (GLS) derived from transthoracic echocardiography (TTE) has emerged as a sensitive marker of myocardial dysfunction and may provide complementary information regarding myocardial involvement. Aim: The aim of our study was to evaluate the diagnostic value of transthoracic echocardiography (TTE) with 2D global longitudinal strain (GLS) to detect the degree of myocardial fibrosis (LGE) in patients with LV hypertrophy (LVH). Methods: A total of 95 consecutive patients referred for cardiovascular magnetic resonance (CMR) because of suspected hypertrophic cardiomyopathy or left ventricular hypertrophy were screened for eligibility. After applying exclusion criteria and excluding patients with alternative diagnoses or inadequate image quality, 83 patients were included in the final analysis. All the participants underwent both CMR and transthoracic echocardiography with GLS assessment. Results: The final study population included 83 patients (57.5 ± 13 years; 66% males). CMR confirmed HCM in 58 (70%) patients, including 23 with left ventricular outflow tract obstruction (LVOTO). The remaining patients demonstrated varying degrees of left ventricular hypertrophy that did not fulfill established diagnostic criteria for hypertrophic cardiomyopathy. Cardiovascular magnetic resonance studies (58 cases; 69%) showed a non-ischemic LGE in LV (23% of segments with LGE). GLS in patients with LGE was significantly lower than those without LGE (-13.9 ± 3.6 vs. -15.9 ± 2.7%, p = 0.01). The mean GLS was -14.52 ± 3.5% and showed a moderate positive correlation with the extent of myocardial fibrosis (LGE%LV; r = 0.45, p < 0.01). This relationship remained significant in multivariable regression analysis (standardized coefficient = 0.683; p < 0.05). Moreover, the transthoracic echocardiography GLS showed a significant association for LV LGE (-14.3%; AUC 0.658; p = 0.01, sensitivity 39%, specificity 90%) with a better diagnostic performance for LGE in more than four LV segments (-12.1%; AUC 0.867; p < 0.001, sensitivity 72%, specificity 87%). Conclusions: GLS was independently associated with myocardial fibrotic burden assessed by CMR. Although it cannot replace CMR for tissue characterization, GLS may provide adjunctive information and may help identify patients with greater fibrotic burden. Prospective studies are needed to validate its clinical utility.