Abstract:
:This study is aimed at refining our understanding of the role of vortex formation at mitral mechanical heart valve (MHV) closure and its association with the high intensity transient signals (HITS) seen in echocardiographic studies with MHV recipients. Previously reported numerical results described a twofold process leading to formation of gas-filled microbubbles in-vitro: (1) nucleation and (2) growth of micron size bubbles. The growth itself consists of two processes: (a) diffusion and (b) sudden pressure drop due to valve closure. The role of diffusion has already been shown to govern the initial growth of nuclei. Pressure drop at mitral MHV closure may be attributed to other phenomena such as squeezed flow, water hammer and primarily, vortex cavitation. Mathematical analysis of vortex formation at mitral MHV closure revealed that a closing velocity of approximately 12 m/s can induce a strong regurgitant vortex which in return can instigate a local pressure drop of about 0.9 atm. A 2D experimental model of regurgitant flows was used to substantiate the impact of vortices. At simulated flow and pressure conditions, a regurgitant vortex was observed to drastically enlarge micron size hydrogen bubbles at its core.
journal_name
Ann Biomed Engjournal_title
Annals of biomedical engineeringauthors
Rambod E,Beizai M,Sahn DJ,Gharib Mdoi
10.1007/s10439-007-9293-ysubject
Has Abstractpub_date
2007-07-01 00:00:00pages
1131-45issue
7eissn
0090-6964issn
1573-9686journal_volume
35pub_type
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journal_title:Annals of biomedical engineering
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journal_title:Annals of biomedical engineering
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journal_title:Annals of biomedical engineering
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