Abstract 9042: Left Ventricular End Systolic Cross-Sectional Area Shows Strong Correlation with Short Axis Untwisting Rate
Background: The untwisting rate of the left ventricle (LV) has been related to early diastolic filling and is proposed as a sensitive index of diastolic function of the heart. In this investigation, we examined the LV segmental untwisting rate (specifically at the lateral and septal walls) with relation to the efficiency of systolic contraction computed as end-systolic short axis area.
Methods: We analyzed high-resolution image data acquired from the LV of 15 open chest pigs using a 10MHz probe on a GE Vivid 7 Dimension ultrasound system. Apical short axis views were exported to EchoPac PC. With this software, end systolic area was measured by tracing the endocardium at maximum contraction. Using 2D speckle tracking, untwisting rate was recorded at the septal wall and the opposing lateral wall of the heart at the mid cavity level just above the papillary muscles.
Results: The septal untwisting rate (102.9 ± 23.5 deg/s) was significantly greater than the lateral untwisting rate (25.0 ± 13.9 deg/s). Although both showed a strong negative correlation with end systolic area, our results indicate that the septal wall untwisting rate showed a stronger correlation (R = -0.85, p < 0.05) with end systolic area than lateral wall untwisting rate (R = -0.79, p < 0.05).
Conclusions: Septal untwisting rate showed a stronger negative correlation with the end systolic LV cavity area at the mid level than the lateral wall untwisting rate.
- © 2012 by American Heart Association, Inc.