Atrial septal defect closure as second-line therapy in refractory heart failure: a successful case report in a 6-year-old child with phosphoglucomutase 1 deficiency (PGM1-CDG).

Background: Atrial septal defect (ASD) is a common congenital heart defect that remains mainly asymptomatic in childhood. However, when left ventricular (LV) compliance is impaired, as in myocarditis or cardiomyopathy, ASD may lead to severe heart failure due to increased left-to-right shunting and a reduced systemic cardiac output. Case summary: We report the case of a 6-year-old boy with CDG-PGM1 and a large ASD who developed acute refractory heart failure, likely triggered by Parvovirus B19 myocarditis. Despite optimal medical therapy, including immunoglobulins, inotropes, and heart failure medication, he remained dependent on pharmacological support. He was deemed ineligible for heart transplantation due to his underlying metabolic condition; therefore an ASD closure was questioned as a last therapeutic option. A balloon occlusion test showed a mild increase in LV end-diastolic pressure, allowing percutaneous closure using a hand-made fenestrated device. The procedure was successful, leading to rapid weaning from inotropes and full clinical recovery. At 6-month follow-up, LV function was normalized, and the patient was asymptomatic. Conclusion: In selected patients with impaired LV compliance, ASD closure may offer a life-saving therapeutic option. Haemodynamic evaluation with balloon occlusion testing is essential to evaluate closure feasibility and determine the potential need of using a fenestrated device.