SUMMARYThe necropsy findings and characteristic angiocardiographic appearance of left atrial to coronary fenestration are presented. This fenestration is probably a fonne fruste of the developmental complex previously described of termination of the left superior vena cava in the left atrium, atrial septal defect, and absence of the coronary sinus. The partially unroofed coronary sinus provides an alternate or accessory route for blood flow when the atrium has no other functional exit. The angiocardiographic diagnosis is facilitated by selective injection of contrast material in the left atrium (or pulmonary vein) or left superior vena cava when the cava connects to the coronary sinus and left atrium via the fenestration.Congenital fenestration between the coronary sinus and left atrium is rare,'"' and when present may provide an alternative or accessory, though vital, route for the flow of blood in the patient with a severely obstructive, absent, or imperforate atrioventricular connection and inadequate interatrial septal communication.24 8-10 Sometimes, even less frequently, this unusual form of intracardiac fenestration may be an incidental necropsy finding or associated with an otherwise uncomplicated atrial septal defect.2 6 7 Though the morphological appearance of left atrial to coronary sinus window has been recorded in a few instances,'`0 this fenestration is rarely diagnosed during life and we wish, therefore, to present our pathological and angiocardiographic experience with six patients, and to comment on the circulatory and clinical implications of this anomaly.
SubjectsA communication between the floor of the left atrium and coronary sinus (partially unroofed coronary sinus) was identified in six patients. The sex distribution was equal, and the age at diagnosis ranged from 2 months to 9 years and 7 months. The fenestration was diagnosed only at necropsy in two patients; at operation in one Received for publication 2 December 1980 patient, who is still alive; and by angiocardiography and confirmed at necropsy in three.All the patients had laevocardia with situs solitus. Two had obstructive anomalies of the tricuspid valve. A 2-month-old infant had tricuspid atresia, intact atrial septum, ventricular septal defect, and pulmonary stenosis and died after attempted systemic to pulmonary anastomosis. The fenestration was recognised at necropsy. The other patient, a boy aged 9 years and 7 months, had pulmonary atresia, an intact ventricular septum, a diminutive and hypertensive right ventricle, and persistence of the left superior vena cava. The diagnosis of coronary sinus to left atrial window was made by angiocardiography and confirmed at necropsy. The diagnosis was also made angiographically and confirmed at necropsy in two patients with obstructive anomalies of the mitral valve. One had mitral atresia with normal ventriculoarterial connections, and the other, mitral stenosis, Taussig-Bing type double outlet right ventricle, subpulmonary infundibular ventricular septal defect, a small ventricular sep...
