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2. Ventricular Septal Defect
Clinical Presentation: small VSD= no symptoms, large VSD= presents in infants as CHF (tachypnea, poor feeding, failure to thrive, frequent lower respiratory tract infections). Presents with dyspnea and cyanosis if accompanied by increased pulm vascular resistance. Bacterial endocarditis
Harsh holosystolic murmur, best heard at left sternal border. Smaller defects have LOUDER murmurs. **Unlike ASD, murmur results from blood going through defect.
systolic thrill over murmur
mid-diastolic rumble at the apex (increased flow over mitral valve)
With increased pulm vascular resistance: holosystolic murmur diminishes, RV heave, loud P2 closure, cyanosis
Diagnostic Imaging and Testing:
Chest radiograph: small VSD= normal cardiac silhouette, large VSD= cardiomegaly and prominent vascular markings. If Pulm Vascular Resistance, than enlarged pulmonary arteries with peripheral tapering
ECG: If large shunt, LA enlargement and LVH are present. If Pulm vascular disease develops, then add RVH
Echo+ Doppler: location of VSD, direction and magnitude of shunt, estimate RV pressure
Cardiac Cath: increased O2 in RV
Treatment: spontaneous closure in 50% of patients with small and medium VSD’s, surgical closure recommended within first few months of life if patient has CHF or pulmonary vascular disease. If patient has moderate-sized VSD but no Pulm Vascular Disease, then surgical closure can wait until later in childhood. Give prophylactic treatment for endocarditis for all VSD patients.
Etiology: abnormal opening in interventricular septum, 70% in membranous, 20% muscular, 10% below aortic valve or near AV valves
Pathology: hole in interventricular septum, dilation of RV, PA, LA, LV
Pathophysiology: depends on size of defect and relative resistances of pulmonary and systemic vasculature. Left to right shunt. If shunt is large, volume overload occurs in RV, pulm circulation, LA and LV, resulting in increased stroke volume. Over time, volume overload causes chamber dilatation, systolic dysfunction, and heart failure. Increase in pulm vascular resistance causes Eisenmenger syndrome Epidemiology: common (2-4/1000)