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 64-year-old presents with dyspnea and edema. He had previous coronary bypass surgery 5 years ago, which was uncomplicated. Since then he has had no further chest pain. On examination, his JVP is at 8 cm, with prominent Kussmaul's sign. The heart sounds are easily heard but there is an early diastolic filling sound (pericardial knock).For the above patient with shortness of breath and peripheral edema, select the most likely diagnosis.
assistant
The correct answer is  A pericardial knock is characteristic of constrictive pericarditis. It is in fact an early S3, occurring 0.06-0.12 seconds after aortic closure. SI and S2 are frequently distant.