Which Doppler signal is most consistent with significant aortic valve regurgitation?

In significant aortic valve regurgitation (AR), the continuous wave Doppler signal across the valve demonstrates a rapid decline in regurgitant jet velocity, resulting in a pressure half-time (PHT) less than 250 milliseconds. A short PHT indicates severe AR with rapid equalization of aortic and left ventricular pressures during diastole.

Pulsed wave Doppler forward flow in the abdominal aorta evaluates stroke volume but does not directly indicate AR severity. Vena contracta to LVOT diameter ratio less than 25% would indicate mild AR, not significant. Peak velocity ≥4.5 m/s is more characteristic of aortic stenosis rather than regurgitation.

This criterion for AR severity using CW Doppler PHT is described in the "Textbook of Clinical Echocardiography, 6e", Chapter on Aortic Regurgitation Doppler Assessment【20:375-380†Textbook of Clinical Echocardiography】.