Assessment of global left ventricular function by tissue Doppler imaging

Recently, an easily measured Doppler index of combined systolic and diastolic ventricular myocardial performance (the Tei index) was proposed as a potentially useful predictor of global cardiac function.(1-10) This index is defined as (a - b)/b, where a is the interval between end and onset of the mitral inflow, and b is the ejection time of left ventricular (LV) outflow (Figure 1). However, there is an important limitation in that the interval between the end and the onset of mitral inflow and ejection time is measured sequentially and not on the same cardiac cycle. Because of this, results are probably less reliable in the presence of heart rate fluctuation. Tissue Doppler imaging (TDI), however, enables us to simultaneously measure contraction and relaxation velocities from myocardium.(11-14) Mitral annular velocities obtained from the apical 2-chamber view show 3 major distinctive waves: a positive wave toward the apex during systole (S) and 2 waves away from the transducer during diastole. The first diastolic wave occurs during early filling, and the second corresponds to atrial contraction. Using TDI, the time interval between the end and the onset of mitral annular velocities during diastole (a') minus the duration of the S wave (b') divided by W (i.e., (a'- b')/b') (Figure 2) may approximate the Tei index obtained by the conventional Doppler method. This study compares the modified Tei index by TDI with the Tei index by the conventional Doppler method.