Alteration of the left ventricular contractile reserve in heart transplant patients: a dobutamine stress strain rate imaging study - Sebbag, L.; Bergerot, C.; Jamal, F.; Roussoulieres, A.; Boissonnat, P.; Bastien, O.; Obadia, J.F.; Barthelet, M.; Ovize, M. (Transplantation Proceedings, 2003)