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Thin myocardial walls and highly variable geometry present challenges in strain imaging of RV using conventional motion analysis programs designed for LV.
Five open chest pigs were studied. High resolution 3D full volume RV image loops were acquired with X7-1 Matrix probe on Philips IE33 ultrasound system at volume rate > 24 vps. After acquiring baseline data, each pig was subjected to overdrive pacing from different epicardial sites (RV free wall, RV Apex, RVOT) allowing heart to recover to baseline for > 15 minutes after pacing from each site. Image data was acquired at each pacing state and analyzed in a met lab based high resolution motion analysis program.
At baseline, radial strain decreased (from 28 ± 6% to 18 ± 4.8%) but longitudinal strain increased (from 21.5 ± 3.45% to 14.65 ± 2.6%) from apex to base with all segments reaching peak at the same time. Pacing from RV free wall and RV apex increased radial strain significantly, but pacing from RVOT slightly reduced radial strain when compared to baseline. Not all the segments showed peak at the same time except RVOT pacing. At each state, echo derived strain values correlated well with sono derived strain values (r>0.82) with Bland-Altman analysis showing all data points within limits of agreement.
New high resolution 3D motion analysis is feasible to evaluate segmental RV mechanical function and RVOT pacing preserve mechanical synchrony.
Poster Sessions, Expo North
Saturday, March 09, 2013, 3:45 p.m.-4:30 p.m.
Session Title: Imaging: Echo: RV Imaging
Abstract Category: 18. Imaging: Echo
Presentation Number: 1179-331
- 2013 American College of Cardiology Foundation