P4.05 An Examination of the Cardiac Mechanics and Pulse Pressure Waveforms That Underpin Ventricular-Arterial Interaction At Rest and During Exercise

Abstract

Background

In healthy humans the left ventricle (LV) and the arterial system reciprocally interact to meet the circulatory demands of the body both at rest and during exercise. Ventricular-arterial interaction (VAI) can be quantified non-invasively using the ratio of arterial (E_a) and ventricular (E_es) elastances. However, E_es is a global measure of LV systolic function and E_a does not take into account the effect of wave reflections. Speckle tracking echocardiography (STE) and pulse wave analysis (PWA) allow for regional quantification of both cardiac and vascular functioning throughout the cardiac cycle. The purpose of this study was to characterise VAI using STE and PWA to explore the LV mechanics e.g. LV twist, and components of the pulse pressure waveform e.g. augmentation index (AIx), that underpin VAI at rest and during exercise.

Methods

9 (7 male) healthy participants (43±7 years) underwent simultaneous STE and PWA at rest and during exercise.

Results

During exercise there was a decrease in E_a/E_es due to significant changes in E_es but not E_a Whilst there were no significant changes in E_a during exercise both AIx and time to forward wave were significantly reduced. In contrast, the alteration in E_es was paralleled by significant changes in peak twist, time to peak twist, untwisting velocity and apical rotation.

Conclusions

The combined use of STE and PWA appears more sensitive to acute physiological changes induced by exercise than the classic VAI ratio: E_a/E_es. Future work will examine the sensitivity of combining STE and PWA to unmask subclinical cardiovascular pathology.

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