CAN TRANSMITRAL DOPPLER E-WAVES DIFFERENTIATE HYPERTENSIVE HEARTS FROM NORMAL

Physiological models of transmitral flow predict E-wave contour altera tion in response to variation of model parameters (stiffness, relaxati on, mass) reflecting the physiology of hypertension. Accordingly, anal ysis of only the E-wave (rather than the E-to-A ratio) should be able to differentiate between hypertensive subjects and control subjects. C onventional versus model-based image processing methods have never bee n compared in their ability to differentiate E-waves of hypertensive s ubjects with respect to age-matched control subjects. Digitally acquir ed transmitral Doppler flow images were analyzed by an automated model -based image processing method. Model-derived indexes were compared wi th conventional E-wave indexes in 22 subjects: 11 with hypertension an d echocardiographically verified ventricular hypertrophy and 11 age-ma tched nonhypertensive control subjects. Conventional E-wave indexes in cluded peak E, integral E, and acceleration and deceleration times. Mo del-based image processing-derived indexes included acceleration ard d eceleration times, potential energy index, and damping and kinematic c onstants. Inter-group comparison yielded lower probability values for model-based compared with conventional indexes. In the subjects studie d, Doppler E-wave images analyzed by this automated method (which elim inates the need for hand-digitizing contours or the manual placement o f cursors) demonstrate diastolic function alteration secondary to hype rtension made discernible by model-based indexes. The method uses the entire E-wave contour, quantitatively differentiates between hypertens ive subjects and control subjects, and has potential for automated non invasive diastolic function evaluation in large patient populations, s uch as hypertension and other transmitral flow velocity-altering patho physiological states.