Abstract 9044: High-Resolution Dynamic Imaging Provides Tools to Evaluate and Monitor Septal Dysfunction After Open-Heart Surgery
Background: Septal dysfunction is a known complication of open-heart surgery.
Methods: Six adult pigs underwent midline sternotomy to expose the heart. Baseline short axis images were acquired with a 10 MHz probe on a GE Vivid 7 Dimension system directly from the heart surface. Animals were on circulatory bypass for 2 hours. After recovery, one of each pair of pigs was subjected to cardiac ischemia for 15 minutes by clamping the aorta proximal to bypass. The pulmonary artery (PA) was partially occluded and RV pressure and cardiac output were monitored. Short axis images were acquired at different stages of PA occlusion. Images were exported to EchoPac PC for offline analysis.
Results: With ischemia, time to peak contraction increased from 31.35% ± 2.65% to 54.90% ± 3.35% of the RR' interval time. The direction of global apical twist was reversed with ischemia and peak twist was reduced from -6.35° ± 1.45° to +3.90° ± 1.35° after bypass with cardioplegia. Differences in the timing of maximal twist between segments were computed as an index of twisting synchrony, which increased from 8.55% ± 0.65% to 16.90% ± 1.25% of the RR' interval with ischemia. Septal function components for strain and twist were most adversely affected. Adverse changes in apical twist showed significant correlation with cardiac output (r>0.8).
Conclusions: Despite improved techniques for open-heart surgery, septal dysfunction is not infrequent. High-resolution dynamic imaging may be useful for monitoring post-op LV segmental mechanics.
- © 2010 by American Heart Association, Inc.