A 67-year-old man comes to the physician for fatigue and lower-extremity edema. Seven months ago, he underwent coronary artery bypass graft surgery and mitral valve repair. His postoperative course has been complicated by paroxysmal atrial fibrillation that is treated with amiodarone and anticoagulation. He also has diet-controlled type 2 diabetes mellitus. The patient is a former smoker with a 35-pack-year history. His blood pressure is 132/77 mm Hg and pulse is 102/min. Jugular venous pressure is estimated at 16 cm H₂O. Cardiac auscultation shows a mid-diastolic murmur. Lungs are clear to auscultation. There is significant ascites and bilateral lower-extremity edema. Electrocardiogram shows sinus tachycardia. Echocardiogram shows enlarged atria, normal left ventricular wall thickness and right ventricular size, and left ventricular ejection fraction of 65%. There is mild mitral regurgitation. Chest x-ray shows normal heart size, clear lung fields, and spotty calcifications along the left heart border. Which of the following is the most likely cause of this patient's symptoms?

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Explanation: 11ec2b69_c114_d0f1_8f63_0543639d9fc3_MD0005_00 This patient's presentation - peripheral edema and elevated jugular venous pressure (JVP) with clear lung fields - is suggestive of right heart failure, most likely due to constrictive pericarditis (CP). Pericarditis is a common complication of coronary artery bypass graft surgery, and some degree of postoperative pericardial effusion develops in almost 85% of patients. Most patients are asymptomatic from small effusions. However, continued pericardial inflammation occurring over months may lead to development of a thickened, fibrous pericardium and constrictive pericarditis. Constrictive pericarditis is an important cause of right heart failure. Patients typically have peripheral edema, ascites, and hepatic congestion with hepatomegaly, which can progress to cirrhosis (cardiac cirrhosis). Other findings may include elevated JVP with prominent "y" descent and hepatojugular reflux, Kussmaul's sign (increase, or lack of decrease, in JVP on inspiration) and pericardial knock (mid-diastolic sound). The electrocardiogram (ECG) in CP may be nonspecific (eg, tachycardia) or can show low-voltage QRS complexes. Chest radiograph often reveals calcified cardiac borders. Echocardiogram may show increased pericardial thickening or calcification, atrial enlargement, and abnormal septal motion; however, these findings are neither sensitive nor specific for the diagnosis. Treatment involves supportive care (eg, anti-inflammatory agents) or pericardiectomy for refractory cases. (Choice A) Long-term amiodarone use is associated with thyroid dysfunction, hepatotoxicity, cardiac bradyarrhythmias, chronic interstitial pneumonitis, neurologic symptoms (eg, ataxia, peripheral neuropathy), blue-gray skin discoloration, and visual disturbances. This patient's right heart failure is not consistent with amiodarone toxicity. (Choice B) Cardiac amyloidosis should be suspected in patients with unexplained congestive heart failure (predominantly diastolic dysfunction), low voltage on ECG, and echocardiogram showing increased ventricular wall thickness with normal left ventricular cavity dimensions (especially in patients without hypertension). (Choice D) Graft closure typically presents with symptoms of angina. ECG may show new ST- or T-wave changes, Q waves, bundle branch block, or arrhythmias suggestive of myocardial ischemia. (Choice E) Superior vena cava syndrome is caused by obstruction of blood flow (typically due to external compression from a tumor). This leads to elevated upper-body venous pressure, with facial swelling and distended neck or chest wall veins. Ascites and lower-extremity edema are usually not present. Educational objective: Constrictive pericarditis is an important cause of right heart failure. It may occur following viral pericarditis or cardiac surgery. Characteristic features include peripheral edema, ascites, elevated jugular venous pressure, hepatojugular reflux, Kussmaul's sign, pericardial knock, and pericardial calcifications on chest radiograph. References: Constrictive pericarditis after cardiac surgery. (http://www.ncbi.nlm.nih.gov/pubmed/23266135)

A 67-Year-Old Man Comes to the Physician for Fatigue and Lower-Extremity