In left-sided heart failure, which organ is primarily affected and may develop edema?

• A. Liver
• B. Lungs
• C. Kidneys
• D. Brain

Answer: (B)

When the left side of the heart fails, blood backs up into the pulmonary circulation, raising pressure in the pulmonary capillaries. This increased hydrostatic pressure pushes fluid out of the vessels into the lung tissue and air spaces, causing pulmonary edema. That edema in the lungs is the characteristic finding of left-sided heart failure, leading to shortness of breath and crackles on exam. Other organs aren’t the primary site of edema in left-sided failure: the liver and peripheral tissues are more typically affected with right-sided (or later, biventricular) failure, while brain edema is not a usual feature.