Assessment of cardiac twist in dilated cardiomyopathy using velocity vector imaging

Abstract

Objectives: Velocity vector imaging (VVI) is a novel echocardiography technique to assess myocardial motion in two dimensions. In this study, we used VVI to assess left ventricular twist (LVtwist) in dilated cardiomyopathy (DCM) patients.

Methods: Twenty DCM patients and 31 normal subjects were evaluated. Echocardiographic images of the long and short axis were processed by VVI software to measure peak rotation angle (ProtA), peak rotation rate (ProtR) in systole. In addition, peak untwisting velocity (Pun-twV) and untwisting rate (unTwR) were measured in diastole. LVtwist was defined as the net difference between the apical and basal angle of rotation, left ventricular torsion (LVtor) was calculated as LVtwist divided by left ventricular diastolic longitudinal length.

Results: The pattern of LVtwist was normal (apex counterclockwise, base clockwise) in 16 DCM patients but abnormal in four. LVtwist and LVtor were significantly decreased (P < 0.01) in DCM compared with normals. In addition, ProtA, ProtR, Pun-twV, and unTwR were all decreased at the basal and apical levels in DCM compared with normals (P < 0.01). There was a significant correlation between ejection fraction and LVtwist in the DCM patients (r = 0.489, P < 0.05).

Conclusions: Cardiac twist is impaired in DCM and this impairment is linked to global dysfunction. VVI is a new noninvasive technology that can be used to assess cardiac twist.