Can ultrasonic tissue characterization predict pathological findings in patients with dilated caldiomyopathy?

Abstract

Background: Systolic wave of the left ventricular(LV) posterior wall motion velocities recorded by pulsed tissue Doppler imaging(TDl) usually consists of 2 components, first and second systolic waves(Swl and Sw2, respectively). However, the mechanism of these waves has not been mentioned. Methods: Subjects consisted of 20 patients with dilated cardiomyopathy(DC group) and age-matched 22 normal subjects(N group). The systolic wall motion velocities along the short and long axes were recorded at the middle of the LV posterior wall in the parasternal and apical long axis views of the LV, respectively, by pulsed TDI. In all patients, the LV pressure curve, its first derivative (dP/dt), and the transthoracic M-made echocardiogram were recorded, and the LV end-diastolic pressure, peak dP/dt, LV end-diastolic dimension, % fractional shortening of the LV and left atrial dimension were measured. Results: 1) The LV end-diastolic pressure, LV end-diastolic dimension and left atrial dimension were significantly greater in the DC group than in the N group. The % fractional shortening of the LVwas significantly lower in the DC group than in the N group. 2) Swl along the long axis was significantly higher than that along the short axis in the N group. However, there were no significant differences in Sw2s between the long and short axes in the N group, and in Swl and Sw2 between the long and short axes in the DC group. 3) Swl and Sw2 were significantly lower in the DC group than in the N group. 4) Swl and Sw2, especially Swl along the long axis, correlated with peak dP/dt in both groups. 5) The peak of Swl almost coincided in time with peak dP/dt. Conclusions: Swl, particularly along the long axis, is a useful parameter for evaluating LV myocardial contractility at isovolumic contraction time. And it was suggested that Swl reflects the spherical change in LV cavity in early systole.