Abstract 366: Evaluation of 2-Dimensional Strain and Strain Rate Predicts Myocardial Viability on the Early Stage of Acute Myocardial Infarction
Background. Assessment of myocardial viability is important for the risk stratification of patients with acute myocardial infarction (AMI). Low-dose dobutamine stress echocardiography (DSE) is useful for the detection of viable myocardium in akinetic area but its accuracy depends on the experience of the readers. Strain image analysis based on 2-dimensional (2D) speckle tracking enables objective and quantitative evaluation of regional myocardial contractility. We investigated whether 2D strain image analysis could detect myocardial viability on the early stage of AMI.
Methods. Myocardial viability was assessed by low-dose DSE on day-3 in 16 patients (age 61±12 years) with AMI, using Vivid-7 (GE Medical Systems). We measured longitudinal and transverse peak systolic strain and strain rate (SR) at baseline and during low-dose DSE within akinetic segments on the apical images.
Results. Low-dose DSE detected viability in 24 out of 48 akinetic segments. The viable segments showed better longitudinal peak strain and SR than nonviable segments at baseline (−10.9±7.4 vs. −2.6±4.1%; p < 0.01, −0.87±0.39 vs. −0.5±0.29 1/s; p<0.01, respectively). There were no significant differences in transverse peak strain or SR (5.4±11.1 vs. 1.3±11.2%; p = 0.21, 0.89±0.61 vs. 0.67±0.53 1/s; p = 0.17, respectively). Significant increases in the longitudinal strain and SR and in the transverse SR were observed during low-dose dobutamine stress only in viable segments. Using −7.1% as the optimal cutoff value, longitudinal strain at baseline detected myocardial viability with 88% of sensitivity, 75% specificity (AUC=0.83). Longitudinal SR at baseline, using −0.64 1/s as a cutoff value, also detected viability with 75% of sensitivity and 71% of specificity (AUC=0.78).
Conclusion. The longitudinal peak strain and strain rate obtained by 2D-strain echocardiography could predict myocardial viability on the early stage of AMI without dobutamine stress.