Thesurgical anatomyoftheconduction tissues

On thebasis ofour collective experience we havereviewed thedisposition ofthe cardiac conduction tissues astheymight beobserved bythesurgeoninbothnormal andabnormal hearts. Thesinus nodelies subepicardially intheterminal sulcus; because ofitsvariable blood supply theentire superior cavoatrial junction isa potential danger area.Thereare no morphologically discrete tractsextending through theatrial tissues betweensinusand atrioventricular nodes. Theatrioventricular node,theatrial extentoftheatrioventricular conduction axis, iscontained exclusively within thetriangle ofKoch.Theaxis penetrates through thecentral fibrous bodyandbranches on themuscular ventricular septumimmediately beneath theinterventricular component ofthemembranous septum. Thelandmarks tothese structures are described astheymight beseenthrough theright atrium, left atrium, andaorta. Consideration is thengiven tothesurgical anatomyoftheabnormal muscular atrioventricular connections that underscore theventricular pre-excitation syndromes. Finally, rules aredeveloped whereby the disposition oftheconduction tissues canbepredicted withaccuracyincongenitally malformed hearts, inthesettings ofbothnormalandabnormal chamber connections. Themostimportant variables inthis respect arealignment between theatrial andventricular septal structures andthe pattern ofventricular architecture present.