Trastuzumab-associated cardiac events in the Persephone trial by Earl, H, Vallier, A, Dunn, J, Loi, S, Ogburn, E, McAdam, K, Hughes-Davies, L, Harnett, A, Abraham, J, Wardley, A, Cameron, D, Miles, D, Gounaris, I, Plummer, C, Hiller, L