Exercise 2D Strain Echocardiography: Is it Feasible?

During the last few decades, the continued growth and expansion of stress echocardiography in daily clinical practice has led to the search and development of new and more quantitative technologies in an attempt to reduce the subjectivity of wall motion analysis by conventional visual method. (1) The evaluation of coronary flow reserve by Doppler echocardiography and myocardial deformation parameters by Tissue Doppler imaging (TDI) and, more recently, by 2D strain have been shown to provide diagnostic and prognostic information in patients with ischemic heart disease. (2-4) 2D strain imaging is a technique based on speckle-tracking echocardiography analysis, where the deformation is obtained by automatic tracking during the cardiac cycle of the distance between two pixels of a myocardial segment during the cardiac cycle. This method enables simultaneous evaluation of the 3 components of myocardial deformation (radial, longitudinal and circumferential), with the advantage of angle independence. The evaluation of longitudinal deformation in this context is particularly important, because subendocardial longitudinal fibers are the first to be affected by myocardial ischemia, while the conventional wall motion analysis is based on myocardial thickening (radial deformation) and endocardial excursion. Moreover, the human eye cannot perceive shorter delays in the onset and termination of myocardial systolic thickening secondary to ischemia, which however can be detected by 2D strain techniques. The group of Lowenstein et al (2) demonstrated the value of longitudinal 2D strain during Dipyridamole stress echocardiography for the diagnosis of ischemia, while Ran et al (5) recently reported the role of this technology during adenosine stress echocardiography for the assessment of myocardial viability. However, the feasibility and value of 2D strain in tests with a significant increase in heart rate have not been entirely established. Some previous experimental and clinical studies have evaluated the value of 2D strain during dobutamine stress echocardiography for the assessment of ischemia and viability. (6-11) However,