The percent change of strain and strain rate under dobutamine stress echocardiography predicts viability following myocardial infarction

Aim. The aim of the present study was to explore the accuracy of the dobutamine-induced percent change of myocardial deformation indices to detect viability following myocardial infarction. Methods. We enrolled 60 consecutive patients presenting for myocardial viability assessment at least 4 weeks following ST-segment elevation myocardial infarction. Strain (S) and strain rate (SR) were individually measured for all myocardial segments, both at rest and during low-dose dobutamine stress echocardiography. The percent change of S and SR from baseline to dobutamine-induced values (at a dose of 20 mu g/kg/min) was calculated individually for each segment. Patients underwent myocardial viability assessment with resting (99)mTc-sestamibi scintigraphy. Based on the results of scintigraphy, the percent change of S and SR was compared between viable and non-viable segments. Results. For all segments, the percent change of both S and SR was significantly higher in viable as compared with non-viable segments (P<0.05 for all). Receiver-operating characteristics curve analysis identified the optimal cut-off value for the percent change of both S and SR that best discriminates viable from non-viable segments in the range of 20-25% with a sensitivity range from 95% to 100%, and a specificity range from 85% to 100%. Conclusion. In patients undergoing viability assessment following ST segment elevation myocardial infarction, the percent change of both S and SR (from baseline to dobutamine-induced values) was significantly higher in viable versus non-viable segments. A cut-off value of 20-25% of the percent change for both S and SR reliably identified viable from non-viable segments with a high sensitivity and specificity for both.