Résumé
To explore the demarcation between the normal variation and the developemental anomaly of the cardiac conduction system (CCS). Using the method of sampling CCS designed by this research group, CCS of 737 cases died of non cardiac causes of death and 149 cases died of sudden cardiac deaths were sampled, serial sections were made, stained with HE method or Masson trichrome method,and observed under the light microscope.Results:(1)There were morphological variations in size, position and structure of normal human CCS; (2) In 4 cases died of sudden cardiac deaths, developemental anomalies were found in both AVN and HB. The morphological variations observed in our cases include: displacement of the bifurcation of HB into the pars membrancea of the interventricular septum,of the HB toward the left or the left lower sides of the interventricular septum or of less than 1/2 AVN into the central fibrous body , as well as of ordinary cardiomyfibers into the HB or BB. The developmental anomalies observed in our cases include: preservation of fetal type AVN in adults, displacement of whole AVN into the central fibrous body, complete division of HB into more than 3 bundles, and the displacement of the bifurcating portion of HB into the root of tricupid valves.