[Determination of systolic left ventricular time interval using the doppler technique. Analysis of aortic flow spectrum with transthoracic echocardiography].

UNLABELLED

In 10 healthy volunteers (age 21-28 years; mean age 24.8 years +/- 1.9 years) systolic left ventricular time intervals (STI) were determined by analysis of aortic Doppler flow pattern. This method was compared with conventional calculation of STI, using electrocardiogram, carotid pulse curve and phonocardiography, which were registered in synchronicity to the Doppler examination. Both, CW- and PW Doppler echocardiography constantly showed slightly lower values than the conventional method. This referred to basic measurements as well as to measurements after the application of isoprenaline and quinidine. The PW Doppler method underestimated the conventional method concerning the electromechanic systole (QS2) by on average 3.98%, the left ventricular ejection period (LVET) by on average 2.24% and the pre-ejection period (PEP) by on average 7.3%. Using CW-Doppler-method, QS2 was on average 5.31% and LVET was on average 6.67% smaller than the values determined by conventional method, whereas PEP was overestimated by on average 1.69%. The study documented that positive and negative inotropic pharmacological effects were measured reliably by the Doppler-echocardiographic method. Isoprenaline caused a significant shortening of frequency corrected QS2 (QS2c) from -55 +/- 17 to -85 +/- 20 ms (p < 0.05) using the PW-Doppler method; frequency corrected PEP (PEPc) was shortened from -40 +/- 14 to -67 +/- 14 ms (p < 0.05). The CW Doppler method also showed a statistically significant reduction of QS2c (from -64 +/- 18 to -89 +/- 25 ms; p < 0.05) and PEPc (from -37 +/- 16 to -64 +/- 12; p < 0.05). Likewise, the conventional method demonstrated statistically significant shortening of QS2c and PEPc after application of isoprenaline. LVETc did not change in a state of positive inotropy, no matter which method was used for determination. The negative inotropic effect of quinidine, measured by PW-Doppler, resulted in a prolongation of QS2c from -55 +/- 16 to -32 +/- 24 ms (p < 0.05) and of LVETc from -20 +/- 11 to +6 +/- 17 ms (p < 0.05). Using CW Doppler method, quinidine led to a lengthening of QS2c from -63 +/- 16 to -42 +/- 22 (p < 0.05) and of LVETc from -33 +/- 11 to -12 +/- 8 ms (p < 0.05). The conventional method also demonstrated a statistically significant increase of QS2c and LVETc. None of the 3 methods in question showed a statistically significant alteration of PEPc in the negative inotropic state.

CONCLUSIONS

Doppler-echocardiographic analysis of aortic flow pattern constitutes a new method for the measuring of systolic time intervals. Basic values as well as changes due to positive or negative inotropic effects are reliably determined, in comparison with conventional methods the measurements are slightly lower.