Aims: Two-dimensional speckle-tracking echocardiography (2D-STE) is limited by its inability to track tissue motion in three dimensions. This is particularly relevant in heart transplant recipients, in whom marked translational motion of the transplanted heart is present. We aimed to compare 3-dimensional (3D)- and 2D-STE-derived strain parameters, and to identify clinical features associated with myocardial mechanics in transplant recipients.
Methods and results: In 36 heart transplant recipients, global and regional left-ventricular (LV) longitudinal and circumferential strain (LSt and CSt), and radial displacement (RDisp) were obtained by 3D- and 2D-STE, and their results were compared. 3D-STE deformation from a subset of transplant recipients with preserved ejection fraction was compared with a control group of 25 subjects matched by gender, age, history of hypertension, and ejection fraction. Associations between global LSt and CSt and clinical, echocardiographic, and haemodynamic parameters in transplant recipients were investigated. 3D-STE yielded lower magnitude of global LSt compared with 2D-STE (-13 ± 3 vs. -16 ± 3%, P < 0.001). The inferolateral wall was a source of variation between 3D- and 2D-STE both for LSt and CSt. Inferolateral wall 3D-STE-derived RDisp was greater than that observed in control subjects (7.4 ± 1.2 vs. 6.5 ± 1.7 mm, P = 0.03), while anteroseptal RDisp was lower than controls (4.2 ± 1.0 vs. 7.3 ± 1.6 mm, P < 0.001). Multiple regression analysis demonstrated that 3D-STE-derived LSt was independently associated with NYHA class (P < 0.001), while 2D-STE-derived LSt was not.
Conclusion: Examination of LV mechanics by 3D- and 2D-STE deformation parameters in heart transplant recipients yields significantly discordant results. 3D-STE-derived LSt is independently associated with NYHA class, suggesting a clinically important relationship between functional status and myocardial mechanics.
Keywords: Cardiac mechanics; Heart transplant; Speckle-tracking echocardiography; Three-dimensional echocardiography.