INFLUENCE OF VARIABLE LOADING CONDITIONS ON PULSED DOPPLER INDEXES OFLEFT-VENTRICULAR EJECTION DYNAMICS

To investigate the influence of changes in loading conditions on Doppl er echocardiographic determination of left ventricular ejection dynami cs (peak aortic flow velocity and mean acceleration), pulsed Doppler w as performed on 20 patients from apical 5-chamber view. Doppler aortic flow velocity curves and hemodynamic values (left ventricular pressur e, wedge pressure, and cardiac output) and the first derivative of ven tricular pressure (dP/dt) by tip-transducer catheter were simultaneous ly recorded at baseline and during intravenous infusion of nitroglycer in as well as at baseline and immediately following left ventriculogra phy. During nitroglycerin infusion, the hemodynamic values were reduce d and peak dP/dt remained constant, Doppler aortic peak velocity and m ean acceleration decreased significantly compared with baseline (0.87 +/- 0.11 m/sec vs 1.01 +/- 0.14 m/sec and 8.86 +/- 1.68 m/sec2 vs 10.1 7 +/- 1.88 m/sec2 respectively; both P < 0.001). After ventriculograph y, the hemodynamic values increased and peak dP/dt was still constant, Doppler aortic peak velocity and mean acceleration increased signific antly compared with baseline (1.15 +/- 0.17 m/sec vs 0.98 +/- 0.16 m/s ec and 11.44 +/- 2.06 m/sec2 vs 9.79 +/- 1.88 m/sec2 respectively; bot h P < 0.001). In conclusion, left ventricular ejection dynamics, as ev aluated by pulsed Doppler echocardiography, is modified by mild change s in loading conditions. Therefore, when serially evaluating the inotr opic state of the left ventricle by the Doppler aortic flow velocity p attern, the potential influence of loading conditions should be taken into account.