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Contribution of mitral annular excursion and shape dynamics to total left ventricular volume change
C Carlhäll1, L Wigström, E Heiberg
1Department of Medicine and Care/Clinical Physiology, University Hospital, Linköping University, SE 581 85 Linköping, Sweden. carca@imv.liu.se
Summary
The mitral annulus (MA) excursion contributes significantly to left ventricular (LV) volume changes, accounting for 19% of stroke volume. This finding highlights the MA
Area of Science:
- Cardiovascular Physiology
- Echocardiography
- Cardiac Mechanics
Background:
- The mitral annulus (MA) exhibits complex shape and motion, influencing left ventricular (LV) function.
- Annular excursion contributes to LV volume changes during the cardiac cycle.
Purpose of the Study:
- To quantify the contribution of MA excursion and shape variation to total LV volume change.
- To evaluate the role of MA dynamics in cardiac function.
Main Methods:
- Utilized four-dimensional (4-D) transesophageal echocardiography (TEE) in nine healthy subjects.
- Applied 4-D Fourier series to MA coordinates for segmentation and analysis.
- Calculated annular excursion volume (AEV) using integrated area and excursion data.
Main Results:
- AEV averaged 10 +/- 2 ml, representing 19 +/- 3% of LV stroke volume (52 +/- 12 ml).
- AEV showed a strong correlation with LV stroke volume (r = 0.73; P < 0.05).
- Peak MA area occurred in mid-diastole, with 91% area reduction before LV systole onset.
Conclusions:
- MA excursion is a significant contributor to LV filling and emptying in humans.
- Suggests atriogenic influence and a sphincter-like action of the MA facilitating ventricular filling and valve competence.
- The 4-D TEE method enables noninvasive AEV measurement for studying physiological and pathological conditions.