Left ventricular global longitudinal strain using a novel fully automated method: A head-to-head comparison with a manual layer-specific strain and establishment of normal reference ranges.

BACKGROUND: A novel automated method for measuring left ventricular (LV) global longitudinal strain (GLS) along the endocardium has advantages in terms of its rapid application and excellent reproducibility. However, it remains unclear whether the available normal range for conventional GLS using the manual method is applicable to the automated GLS method. This study aimed to compare automated GLS head-to-head with manual layer-specific GLS, and to identify whether a specialized normal reference range for automated GLS is needed and explore the main determinants. METHODS: In total, 1683 healthy volunteers (men, 43%; age, 18-80 years) were prospectively enrolled from 55 collaborating laboratories. LV GLS was measured using both manual layer-specific and automated methods. RESULTS: Automated GLS was higher than endocardial, mid-myocardial, and epicardial GLS. Women had a higher automated GLS than men. GLS had no significant age dependency in men, but first increased and then decreased with age in women. Accordingly, sex- and age-specific normal ranges for automated GLS were proposed. Moreover, GLS appeared to have different burdens in relation to dominant determinants between the sexes. GLS in men showed no dominant determinants; however, GLS in women correlated with age, body mass index, and heart rate. CONCLUSIONS: Using the novel automated method, was LV GLS higher than when using the manual GLS method. The normal ranges of automated GLS stratified according to sex and age were provided, with dominant determinants showing sex disparities that require full consideration in clinical practice.

Tetramethylprazine attenuates myocardial ischemia/reperfusion injury through modulation of autophagy.

The current study aimed to investigate the effects of tetramethylprazine (TMP) on myocardial ischemia/reperfusion (MI/R) injury and its underlying mechanisms. MI/R rat model and hypoxia/reoxygenation (H/R) cardiomyocytes model were established. CK level and LDH activity were detected to evaluate MI/R and H/R injury. Cell viability was determined by cell counting kit-8 (CCK-8) assay. Cell apoptosis were identified by flow cytometry and autophagy were detected by western blot. Treatment with TMP significantly reduced CK level and LDH activity and decreased myocardial infarct size in MI/R rats. TMP reduced autophagy dysfunction induced by MI/R. Moreover, TMP treatment decreased H/R-induced injury and attenuated autophagy dysfunction in cardiomyocytes. Inhibiting autophagic flux with chloroquine (CQ) decreased the cardioprotection exerted by TMP in vivo and in vitro. Additionally, the effects of TMP on the modulation of autophagy were inhibited by LY294002 (a PI3K inhibitor) in H/R cardiomyocytes. Our findings suggested TMP exerted cardioprotection against MI/R injury by decreasing Beclin-1 associated autophagy dysfunction through PI3K pathway.