Exercise Stress Echocardiography and Tissue Synchronization Imaging of Myocardial Dyssynchrony

Background: Stress echocardiography represents one of the best possible imaging choice for the diagnosis and stratification of patients with coronary artery disease (CAD). However, this imaging technique presents some limitations such as the quality of the image, high inter-observer variability, and the operator-dependent expertise. New technologies have been recently developed to provide an objective, operator-independent, and quantitative analysis of regional myocardial function. Objectives: The aim of this study was to investigate regional myocardial dyssynchrony using tissue synchronization imaging (TSI) during exercise stress echocardiography (ESE). Patients and Methods: The ESE and TSI analysis of left ventricular (LV) segments was performed for 30 patients with CAD previously treated with revascularization therapy (CADr group) and the results were compared to those in 30 healthy subjects (norm group). The echo protocol comprised echocardiographic examinations at baseline, at the peak of exercise, and at 5 minutes after recovery as well as biplane and triplane acquisitions, pulsed wave of mitral flow, continuous wave of tricuspid regurgitation, tissue Doppler at the mitral annulus, TSI with an automatically detected positive time-to-peak velocity (Tp), and the measurement of the maximum activation time delay between myocardial segments and its standard deviation at baseline and peak stress for each patient. Results: The CADr group showed a lower increase in E (P = 0.005), A (P = 0.006), S' (P < 0.001), and E' (P = 0.006) velocities at both baseline and peak stress and a significantly increased ventricular dyssynchrony at baseline and at peak stress (P < 0.01) compared to the norm group. The baseline-peak variations in the CADr group did not show significant dierences. The relationships between the maximum activation delay and the other echocardiographic parameters showed a significant negative correlation with LV ejection fraction (r = 0.217; P = 0.031) and S' velocity (r = -0.393; P < 0.001) and a positive correlation with the E/E' ratio (r = 0.376; P < 0.001). The comparison between the dierent ischemic territories revascularized in terms of the delay in ventricular activation showed the greatest delay in the revascularized territory in 63% of the patients with ischemia. Conclusions: The TSI analysis in patients with CAD may be considered an interesting parameter in addition to the conventional echocardiographic parameters during ESE.