Strain rate measurement by doppler echocardiography allows improvedassessment of myocardial viability inpatients with depressed left ventricular function

Abstract

Objectives: This study sought to evaluate whether objective assessment of the myocardial functional reserve, using strain rate imaging (SRI), allows accurate detection of viable myocardium. Background: Strain rate imaging is a new echocardiographic modality that allows quantitative assessment of segmental myocardial contractility. Methods: In 37 patients (age 58 ± 9 years) with ischemic left ventricular dysfunction, myocardial viability was assessed using low-dose (10 μg/kg body weight per min) two-dimensional dobutamine stress echocardiography (DSE), tissue Doppler imaging, SRI and ¹⁸F-fluorodeoxyglucose (¹⁸FDG) positron emission tomography (PET). The peak systolic tissue Doppler velocity and peak systolic myocardial strain rate were determined at baseline and during low-dose dobutamine stress from the apical views. Results: A total of 192 segments with dyssynergy at rest were classified by ¹⁸FDG PET as viable in 94 and nonviable in 98. An increase of peak systolic strain rate from rest to dobutamine stimulation by more than −0.23 1/s allowed accurate discrimination of viable from nonviable myocardium, as determined by ¹⁸FDG PET with a sensitivity of 83% and a specificity of 84%. Receiver operating characteristic (ROC) curve analysis showed an area under the curve for prediction of nonviable myocardium, as determined by ¹⁸FDG PET using SRI, of 0.89 (95% confidence interval [CI] 0.88 to 0.90), whereas the area under the ROC curve using tissue Doppler imaging was 0.63 (95% CI 0.61 to 0.65). Conclusions: The increase in the peak systolic strain rate during low-dose dobutamine stimulation allows accurate discrimination between different myocardial viability states. Strain rate imaging is superior to two-dimensional DSE and tissue Doppler imaging for the assessment of myocardial viability.