Rates of left ventricular isovolumic pressure rise and fall from the aortic regurgitation velocity signal: description of the method and validation in human beings.

BACKGROUND

Aortic regurgitation results from a pressure gradient across the aortic valve during left ventricular (LV) isovolumic relaxation, LV filling, and isovolumic contraction periods. Assuming the applicability of the simplified Bernoulli equation to this pressure-flow relation and constancy of aortic pressure during LV isovolumic relaxation and contraction periods, one can theoretically obtain estimates of the rates of LV isovolumic pressure fall and rise (deltaP/delta t) from the aortic regurgitation (AR) velocity signal.

METHODS AND RESULTS

Mitral regurgitation (MR) and AR signals were recorded by using the continuous wave Doppler technique in 26 patients with combined mitral and aortic regurgitant lesions. The LV negative deltaP/delta t was obtained by dividing the time taken for the AR velocity to rise from 1 m/sec to 2.5 m/sec into 21 mm Hg, which is the estimated LV pressure drop between these points. In a similar fashion, the LV positive deltaP/delta t was obtained between 2.5 m/sec and 1 m/sec of the fast decelerating portion of the AR signal. The LV negative deltaP/delta t by the AR method ranged from 420 to 3500 mm Hg/sec and correlated well with that obtained by the MR method obtained in a blinded fashion (r = 0.95, p < 0.0001). The mean (SD) difference between the two methods was 30 (129) mm Hg/sec. Similarly, the LV positive deltaP/delta t by the AR method (range 420 to 2625 mm Hg/sec) correlated closely with that obtained by the MR method (r = 0.93, p < 0.0001), with the mean (SD) difference between the two methods being 38 (138) mm Hg/sec.

CONCLUSIONS

Preliminary data presented in this study indicate the feasibility of obtaining a reliable estimate of LV positive and negative deltaP/delta t from the AR velocity profile. Thus the examination of the AR signal may give valuable insights into both LV systolic and diastolic functions.