Presence of pansystolic murmur of mitral regurgitation in a patient with ASD suggests the presence of ostium primum defect with cleft mitral leaflet or a floppy mitral valve with mitral valve prolapse. ECG shows right axis detion in ASD, and extreme left axis detion in ostium primum ASD. Clinical presentation of ostium primum is similar to ostium secundum except that there may be a mitral systolic murmur due to MR and ECG shows left axis detion. Ref: Pediatrics: A Concise Text By SK Kabra, RN Srivastava, 2010, Page 135