Value of S-wave Dispersion of Mitral Annular Tissue Velocity in Predicting the Presence of Significant Coronary Artery Stenosis

Background Coronary artery disease (CAD) is a paramount cause of death. Global and regional left ventricular (LV) systolic function is an important non-invasive marker of CAD. Using tissue Doppler imaging (TDI), we can visualize and measure the low velocities generated by myocardium which are S'-wave, E'-wave, and A'-wave. However, the cutoff values for systolic and diastolic velocities are still unclear. We aimed to examine the value of the S'-wave dispersion of TDI derived mitral annular velocities for the prediction of angiographically significant coronary artery stenosis. Methods We included 120 patients with symptoms suggesting CAD in the study. We excluded patients with previous myocardial infarction, atrial fibrillation, significant valvular disease, and congestive heart failure. All patients had undergone full history taken and clinical examination, complete 12-leads electrocardiography, echocardiographic with assessment of LV systolic and diastolic dimensions, fraction of shortening, ejection fraction, and Doppler derived mitral valve velocities, TDI with measuring of S'-wave, S'-wave dispersion, E'-wave, A'-wave and E'/A' ratio of the septal, lateral, anterior and inferior walls, and coronary angiography. Lesions with ? 70% narrowing in major epicardial artery or ? 50 % narrowing in the left main coronary artery were considered significant. Patients were classified into two groups according to the presence or absence of significant coronary stenosis. Results Clinical and conventional echocardiographic measures were comparable between the two groups. Tissue Doppler measures were comparable between the two groups except E'/A' ratio of the anterior wall which was significantly lower in patients with significant coronary artery obstruction. S'-wave dispersion was significantly higher in patients with significant coronary artery obstruction (p less than0.00001). Sensitivity of S'-wave dispersion ?35 % in predicting significant coronary obstruction was 63.6 %, specificity was 83.7 %, and overall accuracy was 70.8 %. Conclusion S'-wave dispersion may be a good predictor of angiographically significant coronary artery obstruction.