Parasternal Versus Apical View in Cardiac Natural Mechanical Wave Speed Measurements.

Lana B H Keijzer,Martin D Verweij,Johan G Bosch,Daniel J Bowen,Antonius F W Der Van Steen,Mihai Strachinaru,Annette Caenen,Hendrik J Vos,Nico De Jong

doi:10.1109/tuffc.2020.2978299

Abstract

Shear wave speed measurements can potentially be used to noninvasively measure myocardial stiffness to assess the myocardial function. Several studies showed the feasibility of tracking natural mechanical waves induced by aortic valve closure in the interventricular septum, but different echocardiographic views have been used. This article systematically studied the wave propagation speeds measured in a parasternal long-axis and in an apical four-chamber view in ten healthy volunteers. The apical and parasternal views are predominantly sensitive to longitudinal or transversal tissue motion, respectively, and could, therefore, theoretically measure the speed of different wave modes. We found higher propagation speeds in apical than in the parasternal view (median of 5.1 m/s versus 3.8 m/s, , n = 9 ). The results in the different views were not correlated ( r = 0.26 , p = 0.49 ) and an unexpectedly large variability among healthy volunteers was found in apical view compared with the parasternal view (3.5-8.7 versus 3.2-4.3 m/s, respectively). Complementary finite element simulations of Lamb waves in an elastic plate showed that different propagation speeds can be measured for different particle motion components when different wave modes are induced simultaneously. The in vivo results cannot be fully explained with the theory of Lamb wave modes. Nonetheless, the results suggest that the parasternal long-axis view is a more suitable candidate for clinical diagnosis due to the lower variability in wave speeds.

Highlights

H EART failure affects around 1–2% of all adults in developed countries and its prevalence is even more than 10% for people aged above 70 years [1]
For the simulations of the contact force [Fig. 3(c)], a phase speed plot similar to the theoretical A0-mode was found for the transversal particle motion, while a phase speed plot similar to the theoretical dispersion curve of the S0-mode was found for the longitudinal particle motion
An unexpectedly large intervolunteer variability among healthy volunteers was found in the apical view (3.5–8.7 m/s) versus parasternal view (3.2–4.3 m/s)

Summary

Introduction

H EART failure affects around 1–2% of all adults in developed countries and its prevalence is even more than 10% for people aged above 70 years [1]. The clinical course of heart failure is generally regarded as a consequence of structural and/or functional cardiac changes. The assessment of myocardial function primarily relies on the echocardiographic measurement of cardiac volumes, flow, and tissue velocity [1]–[3]. These measurements suffer from load-dependence issues and provide a rather indirect way of evaluating the myocardial function. The myocardial function could potentially be assessed more directly by evaluating cardiac stiffness [4], [5], a measure of the intrinsic cellular composition and structure of the heart muscle. No noninvasive clinical routine method exists for measuring myocardial stiffness

Methods

Results

Discussion

Conclusion