Myocardial Work Index during Dobutamine Stress Echocardiography

Introduction. Dobutamine stress echocardiography is an alternative method to exercise stress echocardiography for the evaluation of ischemia. Recently, the speckle tracking imaging derived, myocardial work index, was suggested for the evaluation of cardiac performance. In this work, we investigated the effects of dobutamine on myocardial work index parameters during dobutamine stress echocardiography.

Material and method. Echocardiography examinations of patients with normal dobutamine stress echocardiography underwent speckle tracking imaging analysis. Myocardial work index parameters were calculated at each dose of dobutamine and compared.

Results and discussion. 286 patients underwent dobutamine stress echocardiography during the study period. 102 patients were excluded due to pre-existed coronary artery disease or ischemia at dobutamine stress echocardiography. 65 patients were excluded due to suboptimal image quality unsuitable for speckle tracking imaging analysis. The remaining 119 patients with normal results were included. The global work index decreased from 2393.3 to 1864.7 mmHg`, p<0.0004. Global constructive work decreased from 2681.7 to 2152.6 mmHg`, p=0.001. Global wasted work increased from 78.8 to 128.3%, p<0.003. Global work efficacy decreased from 96.1 to 91.9%, p<0.00001. Global strain increased from – 19.6 to -23.7%, P<0.00001.

Conclusion. In contrary to the exercise stress echocardiography, dobutamine stress echocardiography results in a decrease of all myocardial work index parameters even in normal subjects.