Complexity of left ventricular strains in response to elevated volumes in healthy adults – Detailed analysis from the three-dimensional speckle-tracking echocardiographic MAGYAR-Healthy Study

INTRODUCTION: Cardiac haemodynamics is described by the Frank-Starling law, which states that the strength of the left ventricular (LV) systolic contraction is related to the LV diastolic filling, with other words LV stroke volume increases as LV volume increases due to the stretching of the myocyte. The purpose of the present study was to examine how the increasing LV volumes affect LV contractility represented by three-dimensional (3D) speckle-tracking echocardiography (3DSTE) -derived LV strains in healthy adults. METHODS: This is post-hoc analysis of the MAGYAR-Healthy Study employing a novel method for technical analysis of echocardiographic datasets. The present study consisted of 301 healthy adults. Due to inferior image quality, 127 subjects have been excluded, therefore the remaining population included 174 subjects (mean age: 32.9 ± 12.1 years, 80 males). All cases have undergone complete two-dimensional Doppler echocardiography extended with 3DSTE. RESULTS: LV global longitudinal (gLS) and area (gAS) strains were lowest in case of the highest LV end-diastolic volume (EDV). LV global radial (gRS) and 3D (g3DS) strains tendentiously increased with increasing LV-EDV. When segmental analysis was performed, increased LV-EDV was associated with increase of basal LV-RS and LV-3DS. Increased LV strains were associated with increased LV ejection fraction (EF) due to higher LV-EDV for LV-gRS (and LV-g3DS), lower LV-ESV for LV-gCS and lower LV-EDV and LV-ESV for LV-gLS (and LV-gAS). With increasing LV-gRS, LV-gCS and LV-g3DS, all LV strains increased except LV-gLS. With increasing LV-gLS, LV-gRS did not show any increase, LV-gCS and LV-g3DS were the highest when LV-gLS was the highest, while LV-gAS increased simultaneously. With increasing LV-gAS, all LV strains increased. CONCLUSIONS: There is a complex contractility pattern of LV segments/regions in response to elevated LV volumes in healthy circumstances.