Wide splitting of S2-
The second hea sound is widelysplit and is relatively fixed in relation to respiration. A mid-diastolicrumbling murmur, loudest at the fouh intercostal space and alongthe left sternal border, reflects increased flow across the tricuspidvalve. In ostium primum ASD, an apical holosystolic murmur indicatesassociated mitral or tricuspid regurgitation or a ventricularseptal defect (VSD).These findings are altered when increased pulmonary vascularresistance causes diminution of the left-to-right shunt. Both thepulmonary outflow and tricuspid inflow murmurs decrease inintensity, the pulmonic component of the second hea sound anda systolic ejection sound are accentuated, the two components ofthe second hea sound may fuse, and a diastolic murmur of pulmonicregurgitation appears. Cyanosis and clubbing accompanythe development of a right-to-left shunt (see "Ventricular SeptalDefect" below). In adults with an ASD and atrial fibrillation, thephysical findings may be confused with mitral stenosis with pulmonaryhypeension because the tricuspid diastolic flow murmurand widely split second hea sound may be mistakenly thought torepresent the diastolic murmur of mitral stenosis and the mitral"opening snap," respectively. Harrison's principle of internal medicine,20th edition,pg no.1546
ASD
MR
PDA
PS
C.V.S