Abstract
AIMS: Global longitudinal strain (GLS) assessed by speckle-tracking echocardiography has been proposed as a parameter able to reflect early changes in left ventricular systolic function at a stage when left ventricular ejection fraction (LVEF) is still normal. This study aimed at assessing prevalence and prognostic value of left ventricular systolic dysfunction (LVSD) assessed by echocardiographic speckle-tracking GLS in a community-based cohort. METHODS AND RESULTS: Participants from the community-based prospective Northern Manhattan Study underwent two-dimensional transthoracic echocardiography as part of the Cardiovascular Abnormalities and Brain Lesions study. Left ventricular systolic function was assessed by LVEF and speckle-tracking GLS. Subjects were followed annually (mean = 4.8 ± 1.5 years) and incident vascular events (ischaemic stroke, myocardial infarction, and vascular death) were reviewed and adjudicated. Of the 708 study participants, 114 (16.1%) had abnormal GLS but normal LVEF (GLS-LVSD), 30 (4.2%) had abnormal LVEF (LVEF-LVSD), and 564 (79.7%) had normal GLS and LVEF (no-LVSD). In multivariate analysis, risk of events was significantly greater in GLS-LVSD [adjusted hazard ratio (HR) = 2.39, 95% confidence interval (CI) = 1.20-4.77] and in LVEF-LVSD (adjusted HR = 3.51, 95% CI = 1.25-9.88) compared with no-LVSD. Among participants with normal LVEF, lower GLS was significantly associated with events (adjusted HR/unit decrease = 1.15, 95% CI = 1.03-1.28) whereas LVEF was not (adjusted HR/unit decrease = 1.01, 95% CI = 0.94-1.07). The GLS prognostic value was incremental to risk factors and LVEF both in the overall population (chi-square change = 7.406, P = 0.006) and in participants with normal LVEF (chi-square change = 6.357, P = 0.012). CONCLUSION: In a community-based cohort, GLS-LVSD was four times more frequent than LVEF-LVSD. GLS-LVSD was a powerful and independent predictor of cardiovascular events. Left ventricular function assessment by GLS may improve cardiovascular risk stratification in subjects with normal LVEF.