The atrial flow regulator is a new self-expandable double-disc fenestrated device providing a calibrated inter-atrial communication. Paediatric reports are scarce. We herein describe a case of complete atrioventricular block complicating the exemption use of an atrial flow regulator in a 5-kg infant with transposition of the great arteries, ventricular septal defect, and right ventricular outflow tract obstruction.

A 6-month-old baby girl, with a history of 2 months of intensive care management and two episodes of cardiac arrest, was transferred from another European country to initiate the “Giessen approach” for end-stage heart failure in children. At the admission, left ventricular ejection fraction was 20%. Severe mitral valve regurgitation and severe left atrial dilatation were present. Right ventricular function was preserved, and tricuspid valve regurgitation was mild. As a result, the patient underwent surgical pulmonary artery banding. Additionally, unloading of the left atrium was achieved by implanting an 8 mm atrial flow regulator device through a hybrid per-atrial approach. Two months after the procedure, the patient was progressively weaned from the inotropes and transferred to the ward.

Transcatheter creation of an interatrial communication using the Occlutech Atrial Flow Regulator Device for pulmonary hypertension or heart failure is well described. We report a case of an 8-year-old boy with a failing Fontan circulation, in whom the Atrial Flow Regulator was used to successfully create a fenestration between the pulmonary artery and left atrium, improving his clinical condition.