Longitudinal Myocardial Deformation is Selectively Decreased After Pediatric Cardiac Transplantation: A Comparison of Children 1 Year After Transplantation With Normal Subjects Using Velocity Vector Imaging

The transplanted heart experiences numerous hemodynamic changes during and after cardiac transplantation. This study sought to evaluate the left ventricular myocardial mechanics in the pediatric heart transplant population using Velocity Vector Imaging (VVI). This study retrospectively evaluated 28 heart transplant recipients by echocardiography 12 months after transplantation. Echocardiograms from 28 age- and gender-matched subjects were used as a control group. Peak global longitudinal and circumferential left ventricular strain, systolic strain rate, and diastolic strain rate were obtained. Student’s t tests were used to assess differences between the two groups (defined as p ≤ 0.05). The peak global left ventricular longitudinal strain was lower in the transplant group (17.21%) than in the control group (22.14%). The transplant and control groups did not differ significantly in terms of their peak global circumferential strain (20.28% vs. 20.79%, respectively). Similar results were observed for longitudinal and circumferential systolic and diastolic strain rates. The transplant patients showed statistically significant reductions in all peak global longitudinal measures compared with those of the control subjects. Circumferential myocardial deformation appears to be preserved in transplant recipients. This could suggest evidence of ischemia given the known myocardial fiber arrangement of longitudinal fibers toward the endocardial surface, which is also more distal in the coronary arterioles.