P621Variation of global longitudinal strain (2D STE) with passive leg lifting maneuver: a marker of myocardial functional reserve?

Introduction

In a normal heart, the passive leg lifting maneuver (LLM) will result in an increase in myocardial contractility, according to the mechanistic concept of the Frank-Starling law. With the progression of myocardial disease this ability is impaired and the myocardial functional reserve (mFR) is reduced (Figure1 – Panel A). The variation of left ventricular global longitudinal strain (as an index of contractile function) with LLM may thus represent a marker of left ventricular mFR.

Purpose

To assess the variation of left ventricular global longitudinal strain (LV GLS) with LLM as a marker of mFR in a healthy population and in patients with myocardial disease (hypertrophic myocardiopathy - HCM and systolic dysfunction patients – SystDysf.

Methods and results

We evaluated the variation of LV GLS by 2-dimensional Speckle Tracking Echocardiography (2D-STE), in response to passive LLM, in a population of 103 individuals (54 healthy individuals, 28 HCM patients and 21 left ventricular SystDysf patients). 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 46±18 years and 55% were women. Increased venous return to the heart during LLM was confirmed by an increase in the maximal diameter of the inferior vena cava (15,1±3,6 vs 20,6±3,8 mm, p<0.001).

There was a significant variation of LV GLS in healthy individuals submitted to LLM (−20,58±3,0 vs −21,5±2,6%, p=0,02, Δ 0,6%, 95% CI 0,1–1,1%). Regarding the HCM and SystDysf groups, no significant change in LV GLS was observed with LLM (−13,2±2,8 vs −12,3±2,9%, p=0,12, Δ +0,6%, 95% CI −1,4 to 0,18% and −10,2±2,5 vs 10,2±2,7%, p=0,79, Δ 0,08%, 95% CI −0,7 to 0,5%, respectively). Figure 1 (Panel B)

Conclusion

To our knowledge, this is the first report describing the use of LV GLS and LLM to assess mFR in this clinical setting. The absolute increase of LV GLS in the healthy population suggests that this may be a reliable method and a sensitive marker to assess the mFR. Conversely, patients with HCM and with SystDysf show poor or no response to the LLM, suggesting, as expected, a low myocardial functional reserve. Given the non-invasiveness and cost-effectiveness nature of this technique, we suggest that this maneuver could pose a feasible way to assess mFR. Further studies are needed to validate this technique and to assess the role of mFR by 2D-STE as a prognostic marker.

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

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.