Most common congenital heart defect. Opening in the interventricular septum → left-to-right shunt (acyanotic). Large defects → pulmonary overcirculation; if untreated may progress to Eisenmenger (shunt reversal → cyanosis).
Signs & Symptoms
Harsh holosystolic murmur at the left lower sternal border (smaller defect = louder murmur). Large: failure to thrive, tachypnea, recurrent respiratory infections, HF signs.