Wide fixed S2 is seen in

If splitting does not vary with inspiration, it is termed a "fixed split S2" and is usually due to a septal defect, such as an atrial septal defect (ASD)The ASD creates a left to right shunt that increases the blood flow to the right side of the hea, thereby causing the pulmonary valve to close later than the aoic valve independent of inspiration expiration.(Refer: OP Ghai's Textbook of Pediatrics, 8th edition, pg no. 401)