The Reproducibility of Global Longitudinal Strain in Normal and Hypertensive Patients: A Single Centre Study

Abstract

Hypertensive patients may encounter early and subtle myocardial changes. Global longitudinal strain (GLS) enables the early detection of left ventricular (LV) systolic dysfunction. Inter-observer variability and training duration are known limitations of GLS. The aims of the study were to: (A) Measure GLS in both normal and healthy individuals; and (B) Test the intra-and-inter observer GLS measurement variability in both groups. The study included 30 participants: 15 healthy individuals (group 1) and 15 hypertensive individuals (group 2) were included using strict exclusion criteria. LV GLS was measured in all participants using two-dimensional speckle-tracking echocardiography. Images were acquired and measured by one sonographer-operator and re-measured by two independent sonographers-observers one and two. Average GLS for group 1(-17.4%+/-1.6). Average GLS for group 2 (-17.0%+/-1.6). Weich-two sample t-test p= 0.46. The average percentage differences of the GLS measurements between the operator and two observer groups had a relatively small delta between groups, the greatest variability was seen in the HTN group (Graph 1). When examining these results further, it showed there was greater variability amongst observer 1 measurements with an average percentage difference of -0.6+/-2.3 in comparison to original operator -0.2 +/-1.8. The average percentage difference in LV GLS for the single operator was less than for the two observers, indicating that the inter-observer variability is an important limitation to consider when analysing measurements. While a statistically non-significant reduction in LV GLS in hypertensive-patients was found, a larger sample size along with allowance for GLS differences between sexes may yield different results.