Sudden death in athletes—Conduction system: Practical approach to dissection and pertinent pathology

Abstract Sudden death does occur in athletes with or without a previous history of arrhythmias. A study of the conduction system is mandatory in these individuals after ruling out all possible causes of sudden death, both at the gross and microscopic levels, as well as toxicological examination. In this article, a brief discussion of those anatomic landmarks in the heart that may be related to the conduction system and the method of study of the conduction system is emphasized. An examination of the conduction system in 14 athletes revealed varying types of anomalies, both congenital and acquired in nature. The congenital abnormalities included abnormally developed sinoatrial (SA) and atrio-ventricular (AV) nodes and AV bundle. The acquired changes included frequent association of mononuclear cell infiltration in the approaches to the SA node and the SA node, fat and fibrosis to a varying degree in all parts of the conduction system, and focal fibrotic scar areas in the ventricular septum. It is evident that these findings were present for a long period of time while the individual was totally asymptomatic. We therefore hypothesize that during an altered physiologic state, these congenital and/or acquired changes may form a milieu for an arrhythmic event to occur and/or promote an arrhythmic event in the vulnerable conduction system, which may in turn trigger varying types of reentry mechanisms, eventually leading to ventricular tachycardia, fibrillation, and sudden death. We also hypothesize that there may be a genetic and/or an autoimmune complex associated in some vulnerable conduction systems.