Attempting and aborting percutaneous closure of a peculiar atrial septal defect: important contribution of multiple real-time imaging modalities.

The case of a 19-year-old female with a neonatal diagnosis of Tetralogy of Fallot and complete atrioventricular (AV) septal defect is described. She had had a corrective surgery at the age of 6. She did well afterwards despite recent complain of fatigability with mild arterial hypoxaemia. Transoesophageal echocardiography depicted a 12 mm atrial septal defect (ASD) with a bidirectional shunt, with features of a defect of the Ostium Primum type. The reason for the bidirectional shunt was unclear, and cardiac catheterization was performed. The presence of an ASD of the Ostium Primum type was confirmed with normal pulmonary arterial pressures and resistances. The distance to the AV valves seemed compatible with the implantation of a small device and percutaneous closure of the ASD was attempted. However, it was noted that the device deployment would cause deviation of the tricuspid regurgitation jet to the left atrium. Direct coronary sinus catheterization demonstrated its direct roof opening to the left atrium. The device impaired the drainage of the coronary sinus, actually increasing the right-to-left shunt (Figure 4). The implantation was aborted and surgical correction was proposed. Coronary sinus septal defect is a rare form of ASD. Its diagnosis is often difficult because of non-specific features. In this case, oxygen desaturation at presentation seemed to be explained by the regurgitating jet of the right component of AV valve through the Ostium primum defect into the left atrium. Percutaneous closure of the defect was attempted. However, it became clear that the device-increased the right-to-left shunt is also allowing the diagnosis of an unroofed coronary sinus. Under these circumstances, surgery seemed to be the best option.