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The impact of preload reduction with head-up tilt testing on longitudinal and transverse left ventricular mechanics.

Schneider, C, Forsythe, L, Somauroo, J, George, KP and Oxborough, D (2018) The impact of preload reduction with head-up tilt testing on longitudinal and transverse left ventricular mechanics. Echo Research and Practice. ISSN 2055-0464

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Abstract

BACKGROUND: Left ventricular (LV) function is dependent on load, intrinsic contractility and relaxation with a variable impact on specific mechanics. Strain (ε) imaging allows the assessment of cardiac function however the direct relationship between volume and strain is currently unknown. The aim of this study was to establish the impact of preload reduction through head-up tilt (HUT) testing on simultaneous left ventricular (LV) longitudinal and transverse function and their respective contribution to volume change. METHODS: A focused transthoracic echocardiogram was performed on 10 healthy male participants (23 ± 3 years,) in the supine position and following 1 min and 5 min of HUT testing. Raw temporal longitudinal ε (Ls) and transverse ε (Ts) values were exported and divided into 5% increments across the cardiac cycle and corresponding LV volumes were traced at each 5% increment. This provided simultaneous LV longitudinal and transverse ε and volume-loops (deformation-volume analysis - DVA). RESULTS: There was a leftward- shift of the ε -volume loop from supine to 1 min and 5 min of HUT, p<0.001). Moreover, longitudinal shortening was reduced (p<0.001) with a concomitant increase in transverse thickening from supine to 1min, which was further augmented at 5min (p=0.018). CONCLUSIONS: Preload reduction occurs within 1 minute of HUT but does not further reduce at 5 minutes. This decline is associated with a decrease in longitudinal ε and concomitant increase in transverse ε. Consequently, augmented transverse relaxation appears to be an important factor in the maintenance of LV filling in the setting of reduced preload. DVA provides information on the relative contribution of mechanics to a change in LV volume and may have a role in the assessment of clinical populations.

Item Type: Article
Subjects: R Medicine > RC Internal medicine > RC1200 Sports Medicine
Divisions: Sport & Exercise Sciences
Publisher: Bio Scientifica
Related URLs:
Date Deposited: 08 Jan 2018 09:13
Last Modified: 14 Sep 2018 19:19
DOI or Identification number: 10.1530/ERP-17-0064
URI: http://researchonline.ljmu.ac.uk/id/eprint/7784

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