Figure 4.

Measurements of systolic rebound stretch (SRS),26 strain delay index (SDI)21 and radial discoordination index (RDI).28 (A) Within the systolic phase, the strain curve is classified as systolic total shortening (STC, red), systolic pre-stretch (SPS, green) and SRS (blue). SRS is the cumulative amount of systolic stretching after early systolic shortening. (B) SDI is the sum of differences between the peak strain (ε_peak) and the end-systolic strain (ε_ES) across 16 myocardial segments. (C) Radial discoordination index is calculated as a ratio of the average myocardial thinning to the average myocardial thickening during the ejection phase.