USE OF DOPPLER-DERIVED LEFT-VENTRICULAR TIME INTERVALS FOR NONINVASIVE ASSESSMENT OF SYSTOLIC FUNCTION

Historically, left ventricular (LV) systolic time intervals obtained using an electrocardiogram, phonocardiogram and carotid arterial pulse tracing have been used to assess LV function noninvasively. Although these intervals can be derived from Doppler data,1 there are few studies validating this approach.2 The ratio of the preejection period (PEP) to LV ejection time (LVET) has provided the most useful index of systolic function.3 In patients with systolic dysfunction, PEP lengthens due to a reduction in LV pressure development during isovolumic contraction, whereas LVET shortens due to a decrease in the extent of fiber shortening, in some cases with a reduced stroke volume. These changes cause an increase in the PEP/LVET ratio.3 Theoretically, a ratio that also includes the isovolumic relaxation period would improve noninvasive assessment by encompassing LV pressure decay, which also is prolonged in patients with systolic dysfunction. Many patients with systolic LV dysfunction have mitral regurgitation (MR), which encompasses periods of isovolumic contraction, ejection and isovolumic relaxation. Therefore, we postulated that the ratio of LVET to MR duration would provide a useful and potentially better index of systolic function than do conventional systolic time intervals. The purpose of this study was to evaluate the accuracy of Doppler-derived time intervals, including the LVET/MR duration ratio, in assessing LV systolic function. © 1993.