Uhl's Anomaly and Giant Right Atrium: Rare Reasons for Enlarged Right-Sided Cardiac Cavities

Background: Dilatation of the right cardiac cavities can have different reasons. Sometimes, there is rare differential diagnosis beneath common cases (e.g., atrial septal defect).

Method: First, we report a case of Uhl's anomaly—a rare variant of congenital heart disease with loss of the right ventricular myocardium. A 1-year-old with recurrent coughing was admitted to hospital. The subsequently performed X-ray showed a cardiomegaly with pulmonary edema. On echocardiography the right ventricle and right atrium were massively enlarged with a “paper-thin” right ventricular wall and a reduced right ventricular function as well as significant tricuspid insufficiency. The oxygen saturation was 75% and the hemoglobin was elevated as a sign of chronic cyanosis. A reduction plastic of the right atrium and the right ventricle were performed in order to minimize the risk of arrhythmia and thrombosis. Furthermore a total cavopulmonary connection was established because the right ventricle was too insufficient for a “one and a half circulation” after the reduction plastic. The diagnosis of Uhl's anomaly was confirmed by pathology. Myocardial cells of the right ventricular wall were barely detected. Four years after TCPC severe protein losing enteropathy manifested. We performed an interventional re-fenestration of the intracardiac Fontan-tunnel. The patient remained free of pleural effusion and signs of Fontan failure during the subsequent 4-year follow-up until today. The second case is about a congenital aneurysm of the right atrium (giant right atrium). The enlargement of the right atrium was diagnosed prenatal. The infant was born mature and did not show any symptoms of cardiac failure. The echocardiography showed an enlargement of the right atrium (10 cm² in four-chamber view). The tricuspid valve had no dysplasia and only a mild regurgitation. During a 24-hour ECG we could not detect any sign of arrhythmia. The reduction plastic of the right atrium aneurysm was performed at the age of four months. The pathology of the aneurysm showed fibrosis with hardly any cardiomyocytes. After the operation, the MRT showed that the size of the right atrium was reduced (preoperative: 14.1 cm², postoperative: 7.1 cm²). However, a progressive dilatation of the left auricle developed after the operation (8 cm² on four-chamber echo view). Therefore, a reduction plastic of the left atrium was performed.

Conclusion: In summary, these two cases illustrate that there are many different reasons for a dilatation of the right-sided cardiac cavities. It is important to be aware of the rarer causes as the ones presented here.

Publication History

Article published online:
28 January 2023