Abstract 2255: Mechanical Alterations in Single Ventricle Patients Show Much Greater Decreases in Twisting Than the Concordant Decrease in Circumferential Strain: Studies by Analysis of Strain From Gradient Cine Echo Sequences
Background: We have previously shown in echo studies that single ventricle (SV) patients have both significantly decreased twisting and dyssynchrony of twisting which characterize what we believe is an unlooped heart that lacks helical fiber patterns.
Methods: In this multi-center study, 38 children and adults (8 –37 years) with SV of left ventricular type (n=30) or indeterminate type (n=8) were studied. Seventeen were post cavopulmonary anastomosis and 21 were post Fontan. We also analyzed MRI images from 14 normal children and adults who underwent MRI sequences with informed consent, with a clinical indication for CNS abnormalities. Gradient cine MRI sequences close to the apex were compared and subjected to a Vector Velocity Imaging (VVI) analysis program adapted for MRI mechanical function.
Results: For the normals, circumferential strain at this level was −19.3 ± 6%; the point of dispersion of peak circumferential strain was 22.3 ± 28.9 msec. For the SV patients, circumferential strain was −8.0 ± 3.3% and rotation was markedly reduced, to −2.6 ± 1.24° (p < 0.001), with dispersion of the peak of rotation of 166.5 ± 72.4 msec.
Conclusions: Our study shows a dramatic decrease in apical rotation and a modest decrease in circumferential strain in SV patients when compared to patients with normal hearts. Strain mechanics at the apex in the SV patient showed marked dyssynchrony.