Physical finding	Innocent murmur	Atrial septal defect
Precordial activity	Normal	Increased
First heart sound (S1)	Normal	Normal
Second heart sound (S2)	Splits and moves with respiration	Widely split and fixed (i.e., does not move with inspiration)
Systolic murmur (supine)	Crescendo/decrescendo	Crescendo/decrescendo
	Possibly vibratory at lower left sternal border	“Flow” at upper left sternal border
Systolic murmur (standing)	Decreases in intensity	Does not change
Diastolic murmur	Venous hum	Inflow “rumble” across tricuspid valve area