[Morphological observation of Mahaim's fibers in 7 cases].
OBJECTIVE
To investigate the Mahaim's fibers of the cardiac conduction system (CCS) of human hearts and study their morphological features.


METHODS
The CCS from 165 cases of sudden death without extracardiac causes and those from 760 cases of non-cardiac death were sampled using a method established by the authors. Serial sections were prepared for histological observation.


RESULTS
Mahaim's fibers were discovered in 7 cases, 5 cases were in the sudden death group, accounting for 3% in that group, 2 cases were in the non-cardiac death group, accounting for 0.26% in that group. All cases belonged to the bundle-ventricular branch type. The characteristics of Mahaim's fibers were found to be as follows. Their transverse diameter was 10 - 35 microns. The bodies of the Mahaim's fibers that originated from A-V bundle were slender with nucleus in the middle of the cell. While the shape of cells from the left bundle branch varied according to the origin of the Mahaim's fiber with size enlarging from up downward. Both types of cells showed abundant lightly stained cytoplasm, similar to A-V bundle and left bundle branch cells. The cells were not bifurcated and some of them were surrounded by a thin layer of fibrous tissue.


CONCLUSIONS
Mahaim's fibers are not a rarity and it is an abnormal development of an A-V by-path.
Song
Y
Y
Department of Forensic Pathology, Sun Yat-Sen University of Medical Sciences, Guangzhou 510089, China.
Yao
Q
Q
Luo
Z
Z
Zhu
J
J
D000293:Adolescent; D000328:Adult; D016757:Death, Sudden, Cardiac / Q000473:pathology*; D005260:Female; D006329:Heart Conduction System / Q000473:pathology*; D006801:Humans; D008297:Male