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

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. 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. 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. 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.