Mild moderate and severe are clinically defined based on ejection area (cm2), regurgitant flow per beat (ml) and regurgitant fraction (%) under ultrasound Doppler. A jet area <4 with a regurgitant flow per beat <30 and a regurgitant fraction <30 is defined as mild; a jet area 4-8 with a regurgitant flow per beat 30-59 and a regurgitant fraction 30-49 is defined as moderate; a jet area >8 with a regurgitant flow per beat >60 and a regurgitant fraction >50 is defined as severe.