Observations on Doppler mid-diastolic mitral flow reversal.

Mitral regurgitation is detected occasionally in diastole during severe aortic regurgitation, hypertrophic cardiomyopathy and atrioventricular block. We have noticed mitral mid-diastolic flow reversal in both patients and many normal subjects. To evaluate this flow phenomenon, pulsed Doppler mitral flow velocity and M-mode echocardiographic recordings were obtained in 38 normal subjects (age range, 16 to 61 years). Fifteen of 38 subjects (40%) had mid-diastolic flow reversal, defined as reversed flow occurring in mid-diastole with a duration greater than 50 msec. Mid-diastolic flow reversal was more common in subjects with longer RR intervals (1031 versus 893 msec), more rapid M-mode echocardiographic EF (early diastolic deceleration) slopes of mitral valve anterior leaflet motion (141 versus 93 mm/sec), and more rapid deceleration of early diastolic mitral flow velocities (612 versus 426 cm/sec2). Mid-diastolic flow reversal by Doppler color flow mapping was recorded in the left atrium in all subjects, even in subjects without mid-diastolic flow reversal shown by pulsed Doppler echocardiography. However, subjects with mid-diastolic flow reversal detected by pulsed Doppler echocardiography demonstrated greater extension of flow into left atrium (10.4 versus 4.1 mm) and longer duration (112 versus 69 msec) of color flow reversal. These data suggest that mid-diastolic flow reversal represents a physiologic intravalvular flow that is possibly the result of reflected flow from the vigorous early diastolic mitral semiclosure.