Prognostic Value of Left Ventricular Global Longitudinal Strain and Establishment of its Lower Limit of Reference: A Clinical Validation Study

Abstract Introduction: Left ventricular global longitudinal strain (LVGLS) is an advanced echocardiographic parameter quantifying longitudinal myocardial function. Its prognostic utility has been demonstrated in various cardiac conditions. However, the precise definition of its lower limit of the reference range and its predictive value in a large and heterogeneous clinical cohort still require further elucidation. Objectives: The primary aims of this study were: 1) To evaluate the prognostic relevance of LVGLS in a diverse clinical population. 2) To determine the lower limit of the reference range of LVGLS in our cohort. 3) To analyze the ability of LVGLS to predict major adverse cardiovascular events (MACE) independently of other established risk factors. Methods: A prospective cohort study was conducted, including consecutive patients undergoing transthoracic echocardiography at our institution between [Start Date] and [End Date]. Patients with inadequate acoustic windows or incomplete data were excluded. LVGLS was measured using speckle tracking software in apical 2-, 3-, and 4-chamber views. The primary endpoint was the occurrence of MACE, defined as the composite of cardiovascular death, hospitalization for heart failure, non-fatal acute myocardial infarction, and stroke. Baseline characteristics, echocardiographic parameters, and MACE incidence during follow-up were analyzed. ROC curves were used to determine the optimal LVGLS cutoff for predicting MACE, and Cox regression models were used to assess its independent prognostic value.