Normal troponin T levels are less than 0.10 ng/mL. Contraction of grafts was monitored by palpation and scored 0–3. The arrowheads indicate the day of biopsies and the arrow indicates the day of graftectomy. The eight heterotopic cardiac grafts were divided into the three groups based on their rejection profile: (1) healthy-graft group (B226, B225 and B216), (2) rapidly weakened group (B214 and B218) and (3) gradually weakened group (B229, B223 and B228). B226 and B225 were euthanized and B216 died with beating heart grafts, as a result of anemia (during a period when no donor blood was available), ischemia in a leg (associated with an indwelling femoral artery catheter) or spontaneous intra-abdominal hemorrhage, on day 23, 16 or 56, respectively.