Depressed contractile function due to canine mitral regurgitation improves after correction of the volume overload.
AUTOR(ES)
Nakano, K
RESUMO
It is known that long-standing volume overload on the left ventricle due to mitral regurgitation eventually leads to contractile dysfunction. However, it is unknown whether or not correction of the volume overload can lead to recovery of contractility. In this study we tested the hypothesis that depressed contractile function due to volume overload in mitral regurgitation could return toward normal after mitral valve replacement. Using a canine model of mitral regurgitation which is known to produce contractile dysfunction, we examined contractile function longitudinally in seven dogs at baseline, after 3 mo of mitral regurgitation, 1 mo after mitral valve replacement, and 3 mo after mitral valve replacement. After 3 mo of mitral regurgitation (regurgitant fraction 0.62 +/- 0.04), end-diastolic volume had nearly doubled from 68 +/- 6.8 to 123 +/- 12.1 ml (P less than 0.05). All five indices of contractile function which we examined were depressed. For instance, maximum fiber elastance (EmaxF) obtained by assessment of time-varying elastance decreased from 5.95 +/- 0.71 to 2.25 +/- 0.18 (P less than 0.05). The end-systolic stiffness constant (k) was also depressed from 4.2 +/- 0.4 to 2.1 +/- 0.3. 3 mo after mitral valve replacement all indexes of contractile function had returned to or toward normal (e.g., EmaxF 3.65 +/- 0.21 and k 4.2 +/- 0.3). We conclude that previously depressed contractile function due to volume overload can improve after correction of the overload.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=296964Documentos Relacionados
- Irreversible morphological changes contributing to depressed cardiac function after surgery for chronic aortic regurgitation.
- Correlation of degree of left ventricular volume overload with clinical course in aortic and mitral regurgitation1
- Congenital mitral regurgitation due to 'posterior reinsertion' of chordae tendineae.
- Letter: congenital mitral regurgitation due to 'posterior reinsertion' of chordae tendineae.
- Diagnosis of severe mitral regurgitation due to non-rheumatic chordal abnormalities.