Sudden unexpected death occurring a considerable time after surgery in congenital heart disease, especially in tetralogy of Fallot, and after the Mustard procedure for transposition, is well documented. However, studies of the conduction system in these cases of sudden death are rare. Is the sudden death related to the previous surgery? Is it related to the changes in the anatomy or electrophysiology after surgery in some cases? Or is it similar to the unknown cause of sudden death seen in the general young population?
Studies of the conduction system in our four cases reveal abnormalities in this system which may be significant in the etiology of sudden death.
The first point to consider is the feet that in three cases, (1, 3, and 4), there was marked fibrosis, and arterio- and arteriolosclerosis of the summit of the ventricular septum, far beyond that seen normally in the respective ages. These changes were often associated with alteration in the central fibrous body and the pars membranacea. This anatomic pathology may be due to the altered hemodynamics after the operative procedure and possibly to the effects of the surgical handling of the heart. And since the conduction system lies within or adjacent to the fibrous skeleton of the heart, it may be affected by the changes of this skeleton, resulting in sudden death.