Pediatr Cardiol 12:241-242, 1991

Pediatric Cardiology 9 Springer-Verlag New York Inc. 1991

A n o m a l o u s S y s t e m i c V e n o u s to L e f t A t r i a l C o n n e c t i o n in T r i c u s p i d A t r e s i a with S e v e r e l y R e s t r i c t i v e Interatrial C o m m u n i c a t i o n Gerard Holmes, Armin J. Wagman, and Michael L. Epstein Division of Pediatric Cardiology, University of Florida College of Medicine, Gainesville, Florida, USA

SUMMARY. An adequate interatrial communication is necessary to accommodate right atrial output in patients with tricuspid atresia. We report a patient with a tiny opening in the midportion of the atrial septum, who was found to have an anomalous systemic venous to left atrial communication. This channel was not evident on noninvasive testing, but would likely have caused persistent desaturation following a Fontan procedure had it not been detected. In patients with restrictive interatrial communications, an angiogram of the right atrium may reveal similar anomalous channels. KEY WORDS: Tricuspid atrisia - - Interatrial communication

Tricuspid valve atresia mandates adequate interatrial communication to accommodate right atrial output. The interatrial communication usually exists in the form of a secundum-type atrial septal defect, a patent foramen ovale, or, less commonly, an ostium primum or other type of atrial septal defect Ill. Restriction to interatrial communication occurs infrequently, with a reported incidence of 3% in one large patient series [3]. However, when present, it results in systemic venous congestion, reduced systemic output, and worsened hypoxemia. Death may result without appropriate intervention. We report a patient with tricuspid atresia, normally related great arteries, and a highly restrictive interatrial communication in whom survival has been permitted by the presence of an unusual, anomalous systemic venous to left atrial connection.

Case Report An apparently normal infant boy of 32 weeks gestational age was noted to have a harsh grade II/VI holosystolic murmur at age 4 days. Chest roentgenogram revealed situs solitus, moderate cardiomegaly, and pulmonary overcirculation. Electrocardiogram showed a left superior mean frontal QRS axis of-52 ~ left ventric-

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ular hypertrophy with decreased right-sided forces, and right atrial enlargement. Two-dimensional echocardiographic examination, including range-gated and color flow Doppler interrogation, confirmed with clinical suspicion of tricuspid atresia with normally related great arteries. The right ventricle was noted to be moderately hypoplastic with antegrade pulmonic flow supplied through a moderate basilar ventricular septal defect. A small mid-septal interatrial communication was seen, but there was no Doppler evidence for restriction to blood flow. The patient initially did well and required no therapeutic interventions. He was subsequently reevaluated at ages II and 16 weeks, at which times an additional Grade II/VI apical filling murmur was noted in diastole. He remained asymptomatic until age 7 months, when he developed increased respiratory effort and cyanosis. Measurements of arterial blood gases with the patient breathing room air showed a pH of 7.43, pCO2 32 mmHg and pO 2 of 27 mmHg (saturation 57%). Chest roentgenogram showed increased pulmonary parenchymal markings suggestive of chronic lung disease. Barium swallow documented severe gastroesophageal reflux with aspiration. Cardiac catheterization was also performed to evaluate potential cardiac contribution to increased cyanosis. Left ventricular angiography demonstrated filling of a moderately hypoplastic right ventricle through a moderate basilar ventricular septal defect and a second, smaller, mid-muscular ventricular septal defect. There was marked infundibular narrowing during systole. The pulmonic valve was thickened and " d o m e d " during systole. Normal pulmonary venous return to the left atrium with bidirectional atrial level shunting was seen on levophase. Maximum mean pressure difference between the right and left atrium measured 3 mmHg. To provide adequate pulmonary blood flow in the face of significant dynamic infundibular and pulmonary valvar obstruction, a Blalock-Taussig shunt was placed with subsequent improvement in arterial oxygen saturation to 83% with the patient breathing room air. A Nissen fundoplication with gastrostomy

Pediatric Cardiology Vol. 12, No. 4, 1991

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Fig, 1. Left anterior oblique view of superior vena cava (SVC) demonstrating opacification of SVC and right atrium (RA), as well as an anomalous venous connection (arrow) between the posterior, proximal SVC, and the left atrium (LA). tube placement was subsequently performed In address the problems of reflux and aspiration. After recovery from surgery, he was lost to follow-up evaluation for several months. At age 14 months, he developed fever, respiratory distress, and increased cyanosis. On examination he had marked hepatomegaly and decreased right-sided breath sounds. A grade II/VI continuous murmur was heard in the right infraclavicular region, along with a harsh, pansystolic grade IV/VI murmur at the midleft sternal border. Chest roentgenogram showed unchanged pulmonary parenchymal markings with a right-sided pleural effusion and an increase in cardiac silhouette compared to previous studies. Two-dimensional echo/Doppler study confirmed the patency of the shunt and demonstrated a moderate pericardial effusion. It also showed the interatrial communication to be very small with marked thickening of the right atrial wall and leftward bowing of the atrial septum. At repeat cardiac catheterization, there was a 5 mm/Hg mean interatrial pressure gradient. Angiography performed in the proximal superior vena cava showed a tiny mid-septal interatrial communication, but also demonstrated an anomalous venous connection between the proximal superior vena cava and the left atrium (Fig. 1). A Park blade septostomy was performed, followed by a balloon septostomy with elimination of the interatrial pressure gradient and improvement in clinical status.

Discussion

This report describes a patient with tricuspid atresia, normally related great arteries, and moderate right ventricular hypoplasia with significant dynamic infundibular and pulmonary valvar obstruction, who developed progressive restriction to interatrial communication and symptoms of right atrial obstruction. The relative severity of right atrial ob-

struction may have worsened after shunt placement due to increased left atrial pressure from improved pulmonary blood flow. What makes this case unique is the type of anomalous venous connection between the proximal superior vena cava and the left atrium, which was demostrated angiographically but not detected by two-dimensional echocardiography. Other cases of anomalous systemic venous to left atrial connection have been reported in association with tricuspid atresia, including coronary sinus to left atrial communication [4] and persistent left superior vena cava to left atrial connection [2]. To our knowledge, this is the only report of this unusual anomalous channel. However, it is possible that such venous connections may go undetected, considering that right atrial angiograms are not routinely peformed in patients with tricuspid atresia. Moreover, this form of anomalous venous connection may not be readily detected by two-dimensional echocardiography. Thus, the incidence of such an anomalous venous connection, as described here, may be difficult to determine. It is not possible to determine whether the anomalous venous connection was present at birth or developed postnatally, as right atrial angiography was not performed until age 14 months. The functional importance of the anomalous systemic venous to left atrial connection is that it may have permitted survival in the face of a severely restrictive interatrial communication. However, it could cause significant residual right-to-left shunting after Fontan repair if not closed at surgery. Thus, it may be prudent to include right atrial angiograms in the presurgical evaluation of tricuspid atresia when there has been evidence of restriction to right atrial outflow.

Acknowledgment. The authors are indebted to Debbie Floyd for her help in preparing this report.

References 1. Bharati S, McAllister HA Jr, Tatooles CJ, Miller RA, Weinberg M Jr, Bucheleres HG, Lev M (1976) Anatomic variations in underdeveloped right ventricle related to tricuspid atresia and stenosis. J Thorac Cardiovasc Surg 72:383-400 2. Boruchow 1B, Bartley TD, Elliott LP, Schiebler GL (1969) Late superior vena cava syndrome after superior vena cava-Right pulmonary artery anastomosis. N Engl J Med 281:646650 3. Dick M, Flyer DC, Nadas AS (1975) Tricuspid atresia: Clinical course in 101 patients. Am J Cardiol 36:327-337 4. Rose AG, Beckman CB, Edwards JE (1974) Communication between coronary sinus and left atrium. Br Heart J 26:182185

Anomalous systemic venous to left atrial connection in tricuspid atresia with severely restrictive interatrial communication.

An adequate interatrial communication is necessary to accommodate right atrial output in patients with tricuspid atresia. We report a patient with a t...
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