Other forms of left-to-right shunt

Abstract

Five types of L-R shunt are discussed: (1) LV-RA communication, (2) ruptured aortic sinus aneurysm, (3) coronary artery fistula, (4) anomalous origin of the left coronary artery from the pulmonary trunk, and (5) aorticopulmonary septal detect. Although each of these lesions is characterized pathologically by different sites of communication with the right side of the heart, their point or origin is relatively constant, this being the ascending aorta in the last four and the left ventricle in the first. Because the thoracic roentgenogram and oxygen saturation data obtained at cardiac catheterization reveal evidence of a L-R shunt only in the chamber or vessel in which the shunt terminates, specific anatomic diagnosis usually depends upon the performance of both selective left ventriculography and thoracic aortography. The proper choice of diagnostic studies often may be determined before-hand by correlating the plain films with the clinical findings. Although conventional roentgenographic data usually indicate only a L-R shunt or cardiac myopathy, evidence of a continuous murmur suggests strongly that the site of origin of the L-R shunt lies in the ascending aorta.