Atlas-based quantification of myocardial motion abnormalities: added-value for understanding the effect of cardiac resynchronization therapy

Statistical atlases may help improving the analysis of cardiac wall-motion abnormalities. This study aims at demonstrating the clinical value of such a method to better understand the effect of cardiac resynchronization therapy (CRT). We compared an atlas of normal septal motion built using apical four-chamber two-dimensional echocardiographic sequences from healthy volunteers with 88 patients undergoing CRT at baseline and at 12 months follow-up. Abnormal motion was quantified locally using a p value based on a statistical distance to normality. Reduction ≥15% in left ventricle end-systolic volume defined CRT response. Responders showed significantly higher reduction of abnormalities (p ≤ 0.001). Non-responders conserved abnormal septal motion at the end of the isovolumic contraction (IVC). A specific inward-outward motion of the septum during IVC predominated in responders and was corrected at follow-up. The method is of interest to characterize patterns of mechanical dyssynchrony and to study the link between their evolution and CRT response.