| Autor: |
D. Burkoff, David T. Yue, W L Maughan, William C. Hunter, Kiichi Sagawa |
| Rok vydání: |
1988 |
| Předmět: |
|
| Zdroj: |
Developments in Cardiovascular Medicine ISBN: 9789401070843 |
| Popis: |
Early studies of the end-systolic pressure-volume relation of the left ventricle showed that it was identical to the isovolumic relationship; this contrasted with the isolated muscle end-systolic force-length relation which fell to the right of the isometric relationship. A discrepancy similar to that of isolated muscle appeared in later studies of the intact heart in which ejection fraction was greater. Further investigation showed that the discrepancy between end-systolic and isovolumic pressure was dependent on (1) the instantaneous rate of ejection, (2) the ejected volume up to the time of end systole and (3) the peak ejection rate of the same beat; the first of these factors predominated. These results are similar to those found in isolated heart muscle and led us to add a pressure dependent dashpot and fixed elastance to our time varying elastance model; there appears to be a shortening induced deactivation factor in addition. The effect of contractility on the shape of the force-length relationship was also found in the end-systolic pressure-volume relation of the left ventricle. Low contractility (extrasystoles) gave curves convex towards the volume axis; high contractility (post-extrasystolic beats, dobutamine) gave curves concave to the volume axis. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
|
