In utero idiopathic constriction of the arterial duct is a rare condition with only a handful reported cases. Ductal aneurysms with thrombus formations on the other hand are significantly more common. We report a case of a term infant who presented with right heart failure due to premature ductal closure and postnatal severe respiratory distress. Subsequent diagnostics revealed paresis of left laryngeal nerve and obstruction of the left pulmonary artery secondary to a ductal aneurysm. Consequently, surgical intervention was considered necessary. Post-operatively, right ventricular function and hoarseness resolved slowly.