SUBJECTS AND METHODS: Doppler myocardial images at the apical 4 chamber and 2 chamber views were recorded in 28 patients with a left ventricular ejection fraction (LVEF) <45%, and in 18 normal controls. Time intervals from the onset of the QRS complex to the peak systolic velocity were measured at the mid-portion between the basal and mid segments of 4 different ventricular walls (septal, lateral, inferior and anterior);their maximal differences (DIFF) and standard deviation (STD) were calculated and compared.

RESULTS: There were significant differences in the LVEF (30±8 vs. 63±4%, p<0.05) and QRS durations (117±35 vs. 92±9 msec, p<0.05) between the heart failure and control groups. The mean values of DIFF in the heart failure and control groups were 73±32 and 14±6 msec, respectively (p= 0.001). The DIFF and STD showed negative correlations with the LVEF (r=-0.773 with DIFF, r=-0.771 with STD, p<0.001) and positive correlations with the QRS duration (r=0.51 with DIFF, r=0.498 with STD, p<0.001). Fifteen of the patients with heart failure (54%) showed a QRS duration <110 msec; although their QRS duration was not significantly different from that of the normal controls (93±12 vs. 92±9 msec, p>0.05), but the DIFF, from the DMI, was significantly prolonged (61±35 vs. 14±6 msec, p=0.001). The QRS duration showed no significant correlation with the LVEF in the patients with a QRS duration <120 msec (r=-0.276, p= 0.103), but the DIFF showed a significant negative correlation in these patients (r=-0.769, p=0.001).

CONCLUSION: The DIFF and STD, as measured by DMI, are useful in the quantification of ventricular asynchrony, and correlated with other indices known to reflect the left ventricular systolic function.