3077Load dependency of left ventricular longitudinal strain by 2D-speckle tracking echocardiography: myth or reality?

Abstract

Abstract Background 2D-speckle tracking echocardiography (2D-STE) derived strain measurements has been proposed as a non-invasive measure of myocardial deformation and function. However, the effects of left ventricular (LV) loading conditions on 2D-STE derived LV longitudinal strain (GLS) have not been totally elucidated and the results of some studies regarding the load dependency of GLS are controversial. Purpose To characterize the effects of acute load change (preload increase) on LV GLS. Methods and results We evaluated the variation of LV GLS by 2D-STE, in response to a preload increasing maneuver (leg lifting maneuver – LLM), in a population of 30 healthy individuals. Clinical, demographic and echocardiographic parameters (including LV longitudinal mechanics obtained with 2D-STE before and after LLM) were described. The population had a mean age of 27±4 years and 73% were women. Increased preload to the heart with LLM was confirmed by an increase in the maximal diameter of the inferior vena cava (16±3.5 vs 22±3.3 mm, p<0.01). No significant changes in left atrial volume, LV ejection volume and LV ejection fraction were observed in response to the LLM. There was a significant variation of global LV GLS (−21.9±2.3 vs −23.2±1.6%, p<0.001, Δ 1.25%, 95% CI 0.5–1.91) – figure. An increase in right ventricular longitudinal function with LLM (TAPSE 22.5±5.4 vs 25.5±0.5 mm, p=0.005, Δ 2.9, 95% CI 0.9–4.8) was also observed. Conclusion To our knowledge this is the first study performed to assess the effect of preload increase in GLS using the LLM in healthy individuals. In this study, the absolute LV GLS value increased significantly in response to preload increase (LLM). The dependence of GLS on preload is in accordance with the Frank-Starling Law, in which an increase in preload in a healthy individual lead to an increase in myocardial contractility. These findings suggest that LV GLS is a sensitive parameter for detecting subtle changes in LV longitudinal function.