The Use of Global Longitudinal Strain to Detect Subclinical Reduction in Left Ventricular Pump Function

Abstract

Background: Left ventricular (LV) ejection fraction (LVEF) is not a sensitive marker of LV systolic function in a subset of patients with preserved EF. The relation between LV pump function and global longitudinal strain (GLS) has not been elucidated well in patients with objectively preserved EF and no apparent heart failure (HF). We aimed to detect whether LV GLS can discover impaired LV pump function [presented as low stroke volume index (SVI) and low cardiac output (COP)] in patients with objectively preserved EF and no apparent clinical HF and its practice utility. Methods: In total, 100 participants with LVEF of ≥50% were studied for demographic and echocardiographic data, including LVEF, stroke volume, SVI, COP, LV longitudinal strain assessments, apical 4-, 3-, and 2-chamber views averaged for GLS, and were classified into 2 groups: group 1: normal GLS (more negative than −18%) and group 2: low GLS (less negative than −18%). Results: Reduced LV GLS was associated with lower SVI (35.6 ± 13.6 vs. 43.8 ± 12.7 mL/m2; P = 0.01), lesser COP (5.4 ± 1.9 vs. 6.5 ± 2.1 l/min; P = 0.02), GLS had strong positive correlations with SVI (r = 0.75; P < 0.001), and COP (r = 0.66; P < 0.001). LV GLS at a cutoff value less negative than −15% is a strong predictor of SVI ≤35 mL/m2 (76% sensitivity and 79% specificity) and at a cutoff value less negative than −13.5% it is a strong predictor of COP ≤4 L/min (76% sensitivity and 73% specificity). LV GLS was the best independent predictor of low SVI (<35 mL/m2) and low COP (<4 L/min). Conclusion: Impaired LV strain is associated with lower LV pump function, presented as lower COP and lower SVI in patients with preserved EF even in the absence of clinical HF. It is of great importance to incorporate GLS in the routine evaluation of LV function hand-by-hand with the noninvasive assessment of LV stroke volume and COP that can replace GLS on evaluation of LV pump function in old machines with no GLS modalities, for early pick-up of patients with impaired LV pump function before apparent HF.