Novel approach to measure myocardial performance index: pulsed-wave tissue Doppler echocardiography

A simple, reproducible, noninvasive myocardial performance index (MPI) for the assessment of overall cardiac function has been described previously. The purpose of this study was to compare the MPI obtained by pulse Doppler method with the MPI obtained by tissue Doppler echocardiography (TDE) in normal subjects and patients with dilated cardiomyopathy (DCMP). Fifteen patients with DCMP and 15 healthy subjects were included. In order to calculate MPI by TDE, isovolumetric contraction (IVCT), relaxation time (IVRT), and ejection time (ET) were measured at two different sites of mitral annulus: septum and lateral. MPI was calculated by dividing the sum of IVCT and IVRT by ET at each site of measurement. The mean MPI value was found by dividing the sum of these MPI values into two. The same parameters were measured using the mitral inflow and left ventricular outflow velocity time intervals in pulsed Doppler method. At all sites measured, MPI by TDE correlated well with conventional MPI both in healthy subjects and patients with DCMP. The highest correlation was observed in mean values of MPI by TDE:r = 0.94, P < 0.0001in healthy subjects; andr = 0.95, P < 0.0001in patients with DCMP. In conclusion, this study clearly demonstrated that MPI could be measured by TDE and it correlated well with conventional MPI in normal and diseased heart.