Since the original description of an arteriovenous aneurysm by William Hunter,1 innumerable articles have appeared indicating the fascination which this comparatively rare lesion presents both to internists and to surgeons. This fascination has its origin in certain characteristics which are wholly peculiar to this lesion, but which may, in spite of their unique character, aid in a more complete understanding of the phenomena attending other diseases of the circulation.
Objectively, the most striking, though not invariable, phenomenon attending an abnormal communication between an artery and its accompanying vein is a gradual dilatation of the heart and of the blood vessels proximal to the fistula. This dilatation of the heart may be so great as to end in complete cardiac decompensation, as recorded by Reid2 and Leriche,3 or it may be entirely absent. The dilatation is due to the distending force of the increased bulk of blood attracted