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Keywords:

  • dobutamine stress echocardiography;
  • strain rate imaging;
  • myocardial viability

The aim of this study was to evaluate diastolic and systolic strain rate measurements for differentiation of transmural/nontransmural infarction during dobutamine stress echocardiography (DSE). An ameroid constrictor was placed around the circumflex artery in 23 pigs inducing chronic vessel occlusion. Five pigs without constrictor served as controls. During high-dose DSE systolic strain rates (SRsys), systolic and postsystolic strain values (ɛsys, ɛps) and early and late diastolic strain rates (SRE and SRA) were determined. At week 6, animals were evaluated regarding myocardial fibrosis. Histology revealed nontransmural in 14 and transmural infarction in 9 animals. In controls, dobutamine induced a linear increase of SRsys to 12.3 ± 0.4 s−1 at 40 μg/kg per minute (P = 0.001) and a linear decrease of SRE to −6.6 ± 0.3 s−1 (P = 0.001). In the nontransmural group, SRsys, ɛsys, ɛps at rest, and during DSE were higher and SRE was lower than in the transmural infarction group (P = 0.01). Best predictors for viability were SRsys (ROC 0.96, P = 0.0003), SRE at 10 μg/kg per minute dobutamine stimulation (ROC 0.94, P = 0.001) and positive SR values during isovolumetric relaxation at 40 μg/kg per minute dobutamine (ROC 0.86, P = 0.004). The extension of fibrosis correlated with SRsys at rest, ɛsys at rest, and SRE at rest (P < 0.001). For the detection of viability similar diagnostic accuracies of SRE and SRsys were seen (sensitivity 93%/93%, specificity 96%/94%, respectively). Diastolic SR analysis seems to be equipotent for the identification of viable myocardium in comparison to systolic SR parameters and allows the differentiation of nontransmural from transmural myocardial infarction with high diagnostic accuracy. (Echocardiography 2010;27:552-562)