- Doppler echocardiography and tissue Doppler imaging in the healthy rabbit: differences of cardiac function during awake and anaesthetised examination. Stypmann, J., Engelen, M.A., Breithardt, A.K., Milberg, P., Rothenburger, M., Breithardt, O.A., Breithardt, G., Eckardt, L., Cordula, P.N. Int. J. Cardiol. (2007)