Wide fixed split S2 is seen in?

ASD Examination usually reveals a prominent RV impulse and palpable pulmonary aery pulsation. The first hea sound is normal or split, with accentuation of the tricuspid valve closure sound. Increased flow across the pulmonic valve is responsible for a midsystolic pulmonary outflow murmur. The second hea sound is widely split and is relatively fixed in relation to respiration. A mid-diastolic rumbling murmur, loudest at the fouh intercostal space and along the left sternal border, reflects increased flow across the tricuspid valve. ( Harrison&;s principle of internal medicine,18th edition,pg no. 1921 )