Histologic spectrum of the cardiac conducting tissue in non-natural deaths under 30 years of age: an analysis of 43 cases with special implications for sudden cardiac death

In the past, histological findings of the cardiac conduction system or its adjacent structures, such as filiform fibers at the transition from bundle of His to bundle branches, connective tissue at the apex of the ventricular septum, or fibromuscular alterations of the arteries has been considered as a cause of death. However, the prevalence of such findings in a healthy population has been rarely analyzed systematically. In the present study, the morphology of the cardiac conduction system of 43 heart-healthy individuals who died of non-natural causes (ages 0 to 30 years) was investigated. In a high percentage of cases, connective tissue at the apex of the ventricular septum (97.7 %), filiform fibers at the transition from bundle of His to the bundle branches (27.9 %), and fibromuscular proliferations of the sinoatrial node artery (41.9 %), and the AV-node artery (39.5 %) could be detected. Based on our observations, these alterations should not be considered as a pathologic entity or as a cause of death.