Intracardiac Shunts and Role of Tissue Doppler Imaging in Diagnosis and Discrimination

Abstract

Background: We sought to assess right ventricular (RV) systolic and diastolic functions via tissue Doppler imaging (TDI) in order to discriminate right-to-left (bidirectional) from left-to-right intracardiac shunts.

Methods: A tissue Doppler velocity study via Doppler echocardiography was performed in 20 patients with left-to-right shunt (without evidence of significant pulmonary hypertension) and 20 patients with right-to-left shunt or bidirectional shunt (with significant pulmonary hypertension) or Eisenmenger΄s complex and 20 healthy subjects as the control group. RV myocardial performance index (MPI), S wave velocity, E wave velocity, isovolumic relaxation time (IVRT), and isovolumic contraction time (IVCT) from the lateral tricuspid annulus were measured using TDI.

Results: In the patients with left-to-right shunt, the tissue Doppler parameters showed higher S-wave, peak systolic(Sa)/early contraction(Ea) , Sa/IVRT, and Sa/IVCT values; and in the patients with right-to-left or bidirectional shunt tissue, the Doppler parameters showed higher MPI and MPI/Sa value with a high specificity and sensitivity.
Conclusion: We conclude that an evaluation of MPI, S wave, E wave, IVRT, and IVCT via tissue Doppler echocardiography is a useful index for the discrimination of right-to-left from left-to-right and bidirectional intracardiac shunts.