Atypical atrial flutter in a patient with atrial septal defect without previous surgery: the role of septal defect as a part of the arrhythmia substrate.

This case report describes an atypical right atrial septal flutter in a patient with a non-corrected atrial septal defect. The unique feature of this case report is that reentrant tachycardia with a cycle around the atrial septal defect was non-scar related. The slow conduction around this atrial septal defect was probably formed by right atrial dilatation and intra-cardiac haemodynamic alterations.