Color M-Mode Doppler Flow Propagation Velocity Is a Relatively Preload-Independent Index of Left Ventricular Filling

Abstract

Standard Doppler indexes of transmitral filling vary in response to alterations in left ventricular (LV) relaxation or preload. To determine whether color M-mode Doppler flow propagation velocity (v p ), a new index of LV relaxation, is affected by preload, we obtained LV volumes, standard Doppler filling indexes, and v p in 20 patients at baseline, during Trendelenburg’s position, inverse Trendelenburg’s position, and after inhalation of amyl nitrite. LV end-diastolic volume decreased from 111 ± 41 mL at baseline and 116 ± 43 mL during Trendelenburg’s position, to 104 ± 40 during inverse Trendelenburg’s maneuver and 92 ± 33 mL after inhalation of amyl nitrite ( P < .0001). Peak early filling velocity decreased from 79 ± 19 cm/s and 90 ± 20 cm/s to 73 ± 22 cm/s and 64 ± 20 cm/s, respectively ( P < 0.0001). In contrast, no significant changes were found in v p (48 ± 24 and 50 ± 26 cm/s vs 48 ± 25 and 48 ± 25 cm/s). We conclude that v p is not affected significantly by preload. Thus v p may provide a more reliable and independent assessment of LV relaxation. (J Am Soc Echocardiogr 1999;12:129-37.)