LinksrechtsShunts

LinksrechtsShunts, commonly referred to in English as left-to-right shunts, describe abnormal blood flow from the left side of the heart into the right side or into the pulmonary circulation. This creates increased pulmonary blood flow while systemic circulation remains relatively unchanged initially. The condition is typically categorized as an acyanotic congenital heart defect, because the shunt itself does not usually cause immediate central desaturation.

Common causes include atrial septal defects (ASD), ventricular septal defects (VSD), and patent ductus arteriosus (PDA). Other connections, such as certain coronary or systemic-to-pulmonary fistulas, can also produce left-to-right shunts. The key hemodynamic feature is a higher pressure on the left side pushing oxygenated blood into the lower-pressure right-sided chambers or pulmonary arteries, leading to a Qp:Qs ratio greater than 1.

Pathophysiology often involves increased pulmonary blood flow, which over time may cause pulmonary vascular remodeling and potential pulmonary hypertension. If the shunt is large and left uncorrected, this can progress and raise the risk of heart failure in infancy or early childhood. In rare cases, the shunt may reverse (Eisenmenger syndrome) due to progressive pulmonary vascular disease.

Diagnosis typically relies on echocardiography to visualize the defect and quantify shunt size and flow. Additional tools include chest radiography, electrocardiography, and, when necessary, cardiac MRI or catheterization for precise Qp:Qs measurement and hemodynamic assessment.

Management ranges from observation for small defects that may close spontaneously to interventional closure or surgical repair for larger defects. Closure methods include transcatheter device closure for ASD, VSD, or PDA, and surgical repair for complex defects. Prognosis after successful closure is generally favorable, though long-term follow-up is important for monitoring residual defects and pulmonary vascular status.