Abstract 4556: Magnetic Resonance Imaging in Evaluating Left Ventricular Rotation and Synchronization in Patients with Congenital Single Ventricle Disease
Rotational motion of the left ventricular (LV) myocardium has recently received attention as an index of ventricular function. Echocardiographic methods for evaluation of ventricular mechanics are limited by image quality. We developed a method for evaluating cardiac mechanics on gradient cine magnetic resonance imaging (MRI) studies. Twelve adult single ventricle (SV) patients were retroactively selected to compare with 11 randomly selected relatively normal patients who had undergone cardiac MRI study. Detailed SSFP cine images were acquired at several levels in short axis views using Philips and GE MRI systems. Images from each study were evaluated at the apex and papillary muscle levels using VVI (Siemens) for degree of rotation and circumferential strain rate (CSR). Maximal time difference between each segment was recorded as well as the average degree of rotation. When compared with normal patients, SV patients had less rotation at both apex and papillary muscle levels and more dispersion of peak rotation: average rotation: 1.79° ± 0.81° vs. 3.60° ± 1.38°, p < 0.0001, peak rotation: 3.10° ± 1.25° vs 5.71°± 2.63°, p < 0.0001. In contrast, maximum wall motion delay between the segments of each level for data obtained from both rotation and CSR was greater for SV pathology than normals: rotational segment delay, 181.55 ± 76.06 ms vs. 66.86 ± 47.11 ms, p < 0.0001; CSR delay, 90.73 ± 61.98 ms vs. 44.23 ± 37.14 ms, p = 0.004. Average CSR for SV was −8.87 ± 7.30 s−1 and for normals, −18.02 ± 7.31 s−1. Our MRI mechanics study showed decreased CSR in SVs compared to normal LVs, and also a marked decrease in and segmental dyssynchrony of rotation.