Spiral Complex Movements of the Heart Wall at the Beginning of Myocardial Contraction Detected by High Frame Speckle Tracking

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Ischemia causes abnormality in excitation propagation of the local myocardium. Therefore, measuring myocardial contractile movement caused by electrical excitation leads to early detection of abnormalities of cardiomyocytes due to disease. However, the detail mechanism of the transition process in the myocardium from dilation to contraction is still unclear. In the present study, we acquired ultrasonic RF signals with a high frame rate of 1.2 ms using the parallel beam forming by transmitting a plane wave from a sector probe. Furthermore, velocity and displacement in the 2D direction, the ultrasonic beam direction, and the direction orthogonal to the ultrasonic beam (lateral direction), were simultaneously estimated by applying the speckle tracking method, where the cross-correlation coefficient was interpolated so that the spatial resolutions in displacement estimation along the axial and lateral directions were increased to 1.0 and 2.2 um, respectively. We then detected the propagation of contraction response due to electrical excitation along the ultrasound beam and lateral directions around the R-wave of ECG. By showing the instantaneous velocity vector mapping of the ventricular septal wall, just after the Q-wave, the myocardium moved toward the base of the heart and the right ventricle (RV), which corresponds to the expansion. After this, the myocardium began to move to the side of the left ventricle (LV), it began to move towards the apical side a few ms later, and contraction of the LV started. From the S-wave, the myocardium moved so that the LV expanded in the direction of the RV and the base of the heart. The motion then became smaller and contraction of the LV temporarily stopped. Finally, from the end of the first sound, the myocardium moved again to the LV sides and the apex, and substantial contraction of the LV started. The contraction response propagates spirally with 1-4 m/s from Q-wave to the first sound. These results suggest that the proposed method would be useful for evaluating the cardiac contractile function.

Original languageEnglish
Title of host publication2018 IEEE International Ultrasonics Symposium, IUS 2018
PublisherIEEE Computer Society
ISBN (Electronic)9781538634257
DOIs
Publication statusPublished - 2018 Dec 17
Event2018 IEEE International Ultrasonics Symposium, IUS 2018 - Kobe, Japan
Duration: 2018 Oct 222018 Oct 25

Publication series

NameIEEE International Ultrasonics Symposium, IUS
Volume2018-October
ISSN (Print)1948-5719
ISSN (Electronic)1948-5727

Other

Other2018 IEEE International Ultrasonics Symposium, IUS 2018
Country/TerritoryJapan
CityKobe
Period18/10/2218/10/25

Keywords

  • pre-contraction
  • propagation 0f the myocardial contraction

ASJC Scopus subject areas

  • Acoustics and Ultrasonics

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