De Subitaneis Mortibus

Abstract

A twenty-two-year-old woman with type A Wolff-Parkinson-White syndrome had a long history of paroxysmal tachycardia and died of a stroke. Until the last two years of life the tachycardias responded to medical treatment, but thereafter they could only be terminated with electrical shock. During one such shock her sinus rhythm disappeared and for over a year she had only atrioventricular (A-V) junctional rhythm although paroxysms of tachycardia persisted. Special studies of the heart after death included serial sections of the entire A-V ring. Nonspecific degenerative disease of both atria included the internodal pathways. Both the sinus node artery and the A-V node artery were narrowed by mural thickening. The sinus node was generally intact but virtually all atrionodal connections were degenerated. The A-V node was similarly detached from its atrial connections but was in direct continuity with the His bundle. The right bundle branch was interrupted at its origin. Within the central fibrous body there were numerous lacunae and one long cleft extending from atrial to ventricular septum parallel to the A-V node. Although the cleft contained cells, there was no direct A-V connection. At the right lateral A-V junction a long thin cylinder of Purkinje cells lay parallel to the tricuspid valve ring and connected to the atrium but not the ventricle. Beneath the left atrial appendage there was a fault in the mitral annulus through which there was a direct A-V connection. Most of this connection was composed of P cells and thus resembled the patient's own sinus node. The atrial connection was to Bachmann's bundle, which was extensively degenerated. The ventricular connection was to ordinary working myocardium midway between epicardium and endocardium. Some functional implications of these anatomical findings are discussed.