Intraventricular Dyssynchrony Assessment Using Regional Contraction from LV Motion Models
A spatiotemporal 3D left ventricular (LV) motion model was developed to extract regional function for intra left ventricular dyssynchrony (intra-LVD). A finite element model was divided into the standard 17 segments. Temporal interpolation was performed by using periodic control theoretic smoothing splines. Intra-LVD was assessed in terms of systolic dyssynchrony index (SDI) by measuring the dispersion of time to reach peak regional ejection fraction (TPREF). We compared two patient groups: 300 asymptomatic (A: 139M/161F, mean age: 61±9.7 yrs) and 105 patients with myocardial infarction (P: 81M/24F, mean age: 63±10.2 yrs). Consistent regional variation in TPREF was observed in the A group, with the basal septal segments having later TPREF. Omitting these segments significantly reduced the SDI values in both groups (P < .001), but improved the statistical differences between cohorts (P: 8.46±4.15% vs A: 6.03±2.93% with basal septal segments; P: 7.24±4.08% vs A: 4.22±2.27% without). The mean Mahalanobis distance of the P group to the distribution of the A group was increased from 2.66±4.63% to 4.99±8.26% (P < .001). These results strongly suggest that basal septal regions should be removed from intra-LVD indices, to provide better discrimination between the two cohorts.
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