Accidental sizing of patent foramen ovale during atrial septal defect sizing for device

A 21 year old lady with a 22 mm secundum atrial septal defect with adequate rims, and thin septum at the region of the fossa ovalis, but no additional atrial septal defect by transthoracic and transoesophageal echocardiogram was taken up for ASD sizing with a view to device closure. Initially, the ASD was sized to only 8 mm. However, the distal balloon was not fully opened out, and seemed to be conical with restricted opening. Inadvertent passage of sizing balloon through a patent formen ovale(PFO) was immediately confirmed by transthoracic echocardiogram. The ASD was then recrossed and sized to 24 mm with normal opening out of the distal balloon. This was confirmed by transthoracic echocardiogram. A 28 mm ASD device was deployed across the ASD under transthoracic echocardiographic guidance with no residual flow.