MATERIALS AND METHODS: Six mongrel dogs were used for the three heterotopic heart transplantation experiments. The heterotopic hearts were transplanted in the right thoracic cavity using a right thoracotomy. The superior vena cava and left atrial cuff of the donor heart was anastomosed to the superior vena cava and left atrium of the recipient heart. Consequently, the aorta and pulmonary artery were anastomosed to the ascending aorta and right atrial appendage of the recipient heart, without cardiopulmonary bypass. The electrocardiograms of the donor and recipient hearts were measured by electrodes placed at the ventricular apexes and on the skin.

RESULTS: The donor hearts survived for 10, 6 and 18 days after transplantation, without any immunosuppressive agents or anticoagulants. The electrocardiograms of both hearts could be measured using the electrodes. There were no wave or voltage changes on electrocardiography.

CONCLUSION: This working heart model of heterotopic intrathoracic transplantation, without cardiopulmonary bypass, may be useful in studies for various purposes, i.e., the effects of different pharmacological agents on the conduction system of the denervated heart and the hemodynamic changes of the recipient with auxiliary support of the transplanted heart.