A case of congenital heart disease: Truncus aorticus solitarius, single ventricle, and aberrant coronary drainage into the common ventricle

Abstract

A case of congenital heart disease is presented in which a truncus aorticus solitarius was diagnosed because the only vessel leaving the base of the heart was identified as the aorta by angiocardiography. The presence of a functional single ventricle was diagnosed on the basis of the close agreement of oxygen contents in samples obtained from various points in the ventricle and from the peripheral artery. The existence of an aberrant vein draining the myocardium and opening into the common ventricle was indicated by (a) continuous pressure tracings, and (b) the low oxygen content of blood samples taken from this channel. Angiocardiography demonstrated that the pulmonary circulation was via the truncus aorticus solitarius, the descending portion of which gave rise to a large artery supplying the left lung. It is assumed that the right lung received its circulation via small bronchial arteries. The presence of only mild cyanosis at rest, the fluoroscopic contour of the heart and the absence of murmurs are important signs in the clinical diagnosis of a single ventricle. A large vessel from the base of the heart and a visible aortic knob in the posteroanterior position on fluoroscopy in a child indicates the possibility of a truncus. In this patient, the calculated flow through the pulmonary circuit is equal to that through the systemic circuit. The cardiac output from the common ventricle equals that expected from two separate ventricles. However, the heart, working against a single high pressure circuit, has to develop a much higher potential energy than under normal anatomical circumstances. The kinetic energy of this heart is not much increased, mainly because of the large calibre of the single outlet channel. This case is unique in that a review of the literature has failed to reveal any reports of aberrant myocardial venous drainage such as that described above.