Left ventricular twist and untwist in aortic stenosis

Background: To optimally exploit the potential added diagnostic and prognostic value of new left ventricular (LV) deformation parameters, better understanding of LV mechanics in aortic stenosis (AS) is warranted. We sought to determine a broad spectrum of LV rotation parameters in AS patients and age-matched healthy controls, in order to gain insight into the mechanical properties of the LV in AS. Methods: The study comprised 48 AS patients with an aortic valve area < 2.0 cm ² and LV ejection fraction > 50%, and 24 healthy - for age and gender matched - control subjects. LV peak systolic rotation (Rot _max), LV peak systolic twist (Twist _max), untwisting rate (mean diastolic untwisting velocity from Twist _max to mitral valve opening), peak diastolic untwisting velocity, and time-to-peak diastolic untwisting velocity were determined by speckle tracking echocardiography. Results: AS patients had normal basal Rot _max and increased apical Rot _max, resulting in increased Twist _max (13.4 ± 4.0° vs. 11.4 ± 2.7°, P < 0.05). Apical Rot _max and Twist _max correlated significantly to echo-Doppler indicators of AS severity. Time-to-peak diastolic untwisting velocity was increased (20 ± 10 % vs. 15 ± 9 %, P < 0.05) and untwisting rate was decreased (-38 ± 21°/s vs. -50 ± 28°/s, P < 0.01) in AS patients. Conclusions: Twist _max increases proportionally to the severity of AS, which might serve as a compensatory mechanism to maintain systolic LV function. LV diastolic untwisting is delayed and the untwisting rate is reduced in AS.