Dyssynchrony indexes and regional distribution of wall motion. Schematic representation of net dyssynchrony based on spatial distribution of delayed activation. When regions of delayed activation are clustered, the net impact on dysfunction is greater than when they are dispersed. Both situations are associated with similar overall numbers of delayed segments overall, as well as similar variance and dyssynchrony indexes. In contrast, a vector index would be zero for dispersed dyscoordinate shortening but non-zero when dyscoordinate motion is spatially clustered. Reproduced from Helm RH, et al.