system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
A 63-year-old man comes to the physician because of a 3-week history of fatigue and shortness of breath. Physical examination shows diminished breath sounds at the right lung base. An x-ray of the chest shows blunting of the right costophrenic angle. Thoracentesis shows clear, yellow-colored fluid with a protein concentration of 1.9 g/dL. Which of the following is the most likely underlying cause of this patient's pleural effusion?
assistant
Congestive heart failure