[Morphological observations of tumors in the cardiac conduction system].

OBJECTIVE To investigate the incidence of tumors in the cardiac conduction system (CCS) and to study their relation to sudden deaths. METHODS The CCS from 149 cases of sudden death without extracardiac cause of deaths and those from 737 cases of non-cardiac death were sampled using technique designed by the authors. Routine histological examinations were carried out. RESULTS Tumors in the CCS were found in 12 cases (1.35%). Another case with tumor in the CCS was found in a specimen received for consultation. Of these 13 tumors, 10 were primary benign tumors affecting the CCS, 3 were metastatic tumors. The benign tumors included fibroma, hemangioma, lipomatous hypertrophy of the atrial septum, mesothelioma and rhabdomyoma. 8 of the 10 cases were located in the SAN or AVN. All the metastatic tumors were in the SAN. Of the 13 cases, 3 died suddenly. CONCLUSION Tumors in the CCS are the smallest tumors which can cause sudden death.