Significance of Tissue Doppler Echocardiography-Based Dispersion Index of Myocardial Velocities in the Differentiation of Ischemic and Nonischemic Cardiomyopathy: A Novel Echocardiographic Parameter

Abstract

Background: Tissue Doppler imaging (TDI) echocardiography, an objective method for the quantification of left ventricular (LV) function, can detect subtle alterations in contractility both in rest and stress echocardiography. Aim: The study aims were to (1) compare TDI parameters in patients with heart failure (HF) of ischemic and nonischemic etiology, (2) to differentiate both subsets based on velocity dispersion index (VDI) at mitral valve, and (3) to identify parameters that help in identifying the ischemic etiology of HF. Materials and Methods: Patients with symptomatic HF (NYHA class ≥II; LV ejection fraction <40%) were included in the study. Patients with aortic and mitral valve diseases, prosthetic valves, and cor pulmonale were excluded from the study. All patients underwent coronary angiography after stabilization. A total of 100 patients admitted between May 2017 and October 2018 were enrolled. Results: The mean age of presentation was earlier in nonischemic group compared to that of ischemic group of HF (43.4 ± 10.91 vs. 54.06 ± 10.40; P= 0.001). No significant differences in the mitral inflow velocities by conventional Doppler were found. The mean mitral TDI velocities were lower in the nonischemic group compared to those of the ischemic group. Systolic VDI, V s' >25.40 (sensitivity 91.7% and specificity 100%), and diastolic VDI, V e' >17.35 (sensitivity 86.7% and specificity 87.5%), were associated with the probability of diagnosing the ischemic cause of HF. Conclusions: VDIs help in the differentiation of ischemic and nonischemic etiologies of HF compared to the conventional echocardiography.