Session M1.3

Computational Assessment of Spatio-Temporal Heterogeneity of Human Left Ventricular Contractions in Normal and Ischemic Heart

T Chumarnaya*, O Solovyova, SV Sukhareva, VS Markhasin

Institute of Immunology and Physiology of RAS
Ekaterinburg, Russia

To characterize spatio-temporal heterogeneity of left ventricle (LV) regional wall motion we developed a computer program for frame-by-frame analysis of 2D-ultrasound LV images in apical two and four chamber views. The analysis was based on the refined radial and centerline methods for calculation of segmental areas between superimposed end diastolic LV contour and each of the subsequent contours through the cardiac cycle. Global ejection fraction (GEF) was assessed as the difference in the total LV image areas at end diastole and end systole. Regional ejection fractions (REF) were computed as the differences in the diastolic segmental area and the minimal area attained by the given region during inward LV wall motion. Regional asynchronism of LV contraction was characterized by the deviation of the time at which the region achieved REF from the time of end systole. In a group of healthy people (n=22) we found spatially heterogeneous distribution of mean REF along the LV contour with REF peaks of 60% and 63% observed in the mid anterolateral wall and mid inferior septum regions and a minimum REF of 48% in the apical region. The extreme REF differed significantly (p<0.05) from the mean GEF of 51%. Regional asynchronism of wall motion was coordinated with REF magnitudes with strong negative correlation (r=-0.6). In a group of patients with ischemic heart disease (n=52) mean GEF of 45% did not differ significantly from the control. However, mean coefficient of variation in individual REFs was higher in the group of patients (22% vs 15%). The rate of appearance of regions where segmental area exceeded end diastolic value during systole (suggesting regional systolic stretch or regional wall extrusion) was also higher versus control (56% vs 22%). A sub-population of patients (n=17) was sorted out with significantly decreased apical REFs. In this sub-group mean GEF of 38% was significantly below the normal value suggesting that dysfunction of the apical region may be one of the predictors for overall mechanical dysfunctions in the LV. We showed that spatio-temporal characteristics of regional LV motion do change under heart disease and may be useful for clinical diagnostics.

(Abstract Control Number: 194)