| Paper Abstract and Keywords |
| Presentation |
2005-08-18 14:00
Propagation of pulse vibration along heart wall caused by closure of aortic valve
Hiroshi Kanai (Tohoku Univ.) |
| Abstract |
(in Japanese) |
(See Japanese page) |
| (in English) |
Though myocardial viscoelasticity is essential in the evaluation of heart diastolic properties, it has never been noninvasively measured in vivo. By the ultrasonic measurement of the myocardial motion, we have already found that some pulsive waves are spontaneously excited by aortic-valve closure (AVC) at end-systole (T0). In this study, using a sparse sector scan, in which the beam directions are restricted to about 16, the pulsive waves were measured almost simultaneously at about 160 points set along the heart wall at a sufficiently high frame rate. The consecutive spatial phase distributions clearly revealed wave propagation along the heart wall for the first time. The propagation time of the wave along the heart wall is very small, namely, several milliseconds, and cannot be measured by conventional equipment. Based on this phenomenon, we developed a means to measure the myocardial viscoelasticity in vivo. The phase velocity of the wave is determined for each frequency component. By comparing the dispersion of the phase velocity with the theoretical one of the Lamb wave, which propagates along the viscoelastic plate (heart wall) immersed in blood, the instantaneous viscoelasticity is determined noninvasively. This is the first report of such noninvasive determination. In in vivo experiments applied to five healthy subjects, propagation of the pulsive wave was clearly visible in all subjects. For the 60-Hz component, the typical propagation speed rapidly decreased from 5 m/s to 3 m/s around the time of AVC. The typical value of elasticity was about 24-30 kPa and did not change around the time of AVC. The typical transient values of viscosity decreased rapidly from 400 Pa s at T0-8ms to 70 Pa s at T0+10 ms. These values are comparable to those obtained using audio frequency in in vitro experiments reported in the literature. |
| Keyword |
(in Japanese) |
(See Japanese page) |
| (in English) |
heart wall tracking / heart wall vibration / myocardial motion / spatial distribution / phased tracking method / Lamb wave / viscoelasticity / |
| Reference Info. |
IEICE Tech. Rep., vol. 105, no. 230, EA2005-35, pp. 7-12, Aug. 2005. |
| Paper # |
EA2005-35 |
| Date of Issue |
2005-08-11 (EA) |
| ISSN |
Print edition: ISSN 0913-5685 |
| Download PDF |
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| Conference Information |
| Committee |
EA |
| Conference Date |
2005-08-18 - 2005-08-19 |
| Place (in Japanese) |
(See Japanese page) |
| Place (in English) |
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| Topics (in Japanese) |
(See Japanese page) |
| Topics (in English) |
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| Paper Information |
| Registration To |
EA |
| Conference Code |
2005-08-EA |
| Language |
Japanese |
| Title (in Japanese) |
(See Japanese page) |
| Sub Title (in Japanese) |
(See Japanese page) |
| Title (in English) |
Propagation of pulse vibration along heart wall caused by closure of aortic valve |
| Sub Title (in English) |
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| Keyword(1) |
heart wall tracking |
| Keyword(2) |
heart wall vibration |
| Keyword(3) |
myocardial motion |
| Keyword(4) |
spatial distribution |
| Keyword(5) |
phased tracking method |
| Keyword(6) |
Lamb wave |
| Keyword(7) |
viscoelasticity |
| Keyword(8) |
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| 1st Author's Name |
Hiroshi Kanai |
| 1st Author's Affiliation |
Tohoku University (Tohoku Univ.) |
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| Speaker |
Author-1 |
| Date Time |
2005-08-18 14:00:00 |
| Presentation Time |
30 minutes |
| Registration for |
EA |
| Paper # |
EA2005-35 |
| Volume (vol) |
vol.105 |
| Number (no) |
no.230 |
| Page |
pp.7-12 |
| #Pages |
6 |
| Date of Issue |
2005-08-11 (EA) |
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