Here is a continuous-wave Doppler through the mitral valve again—this is just at a higher sweep speed—and the time velocity integral (TVI) through the mitral valve during diastole is 53.1 cm.

The amplitude of the plethysmographic pulse-volume signal and the area under the Doppler velocity signal were correlated. The inter-patient (n=24) correlation ranged from 0.455 to 0.904, with a ...