Objective This in vitro study calculated longitudinal strain (LS) from different ultrasound systems (GE Vivid E9 and Philips IE 33) before and after myocardial infarct (MI) using a vendor‐independent analysis software package (TomTec's 4D LV Analysis) to validate the variation of two ultrasound systems. Methods Ten freshly harvested porcine hearts were passively driven by a pulsatile pump apparatus at stroke volumes (SV) 30–70 mL. Full‐volume three‐dimensional echocardiography (3DE) data were acquired before and after MI using two different ultrasound systems. LS was derived from TomTec and validated against sonomicrometry data. Results Linear regression analyses showed excellent correlations between TomTec‐calculated LS values and sonomicrometry data for both normal and simulated MI groups (GE: R2 = 0.72/0.68, Philip: R2 = 0.71/0.66). Bland‐Altman analyses demonstrated overestimation of echo‐derived strain values for all groups. Both ultrasound system‐derived strain values demonstrated decreased LS after MI, and the average change in strain after infarct was roughly 30% in GE images and 25% in Philips images. Conclusions Both GE and Philips echocardiographic systems can be analyzed with TomTec's program, and these images correlated well with sonomicrometry with acceptable variations.

The authors have withdrawn this preprint due to author disagreement.