Augmented stroke volume (SV) accompanies an increase in ejection velocity (Ve). To determine whether Ve directly affects the LV relaxation rate irrespective of SV changes, the time constant (T) of isovolumic LV pressure (LVP) decay was studied in 8 isolated canine hearts. A water-filled balloon was inserted into LV cavity and instantaneous LV volume was controlled by servo-pump. To eliminate the effect of SV, end-systolic and end-diastolic volumes were clamped and LV was allowed to eject with 3-5 different velocities under two conditions; with mid-ejection time and with end of ejection unchanged. In any condition, T was not significantly altered by Ve changes. Thus, we conclude that LV relaxation rate is not influenced by ejection velocity. Enhanced LV relaxation rate in augmented SV may be due to the direct effect of the extent of muscle shortening.
|Original language||English (US)|
|Number of pages||2|
|Journal||Japanese journal of medical electronics and biological engineering|
|State||Published - Apr 1 1984|
ASJC Scopus subject areas
- Biomedical Engineering