Which statement about left-sided congestive heart failure is true?

• A. It causes pulmonary edema
• B. It causes peripheral edema first
• C. It decreases venous return
• D. It improves with rest

Answer: (A)

When the left side of the heart fails, blood backs up into the lungs, raising pressure in the pulmonary capillaries. That higher hydrostatic pressure pushes fluid out of the capillaries into the interstitial spaces and alveoli, producing pulmonary edema. This pulmonary congestion is what drives the classic symptoms of left-sided heart failure: shortness of breath, crackles on exam, orthopnea, and possibly pink frothy sputum in severe cases. Peripheral edema and systemic venous congestion are more typical of right-sided (or bi-ventricular) failure, not the left side. The idea that the problem is simply decreased venous return isn’t the defining feature of left-sided failure—the hallmark is fluid buildup in the lungs due to backward flow. Rest may relieve some symptoms by reducing demand, but the key concept is pulmonary edema from pulmonary venous congestion.