An 82-year-old man comes to the office due to progressive dyspnea and fatigue over the last year, which now limit his daily activities. He has also noticed bilateral swelling of his feet. The patient has hypertension, which is controlled with amlodipine. His blood pressure is 122/72 mm Hg and pulse is 55/min. Physical examination reveals elevated jugular venous pressure with rapid 'y' descent and a prominent S4. Abdominal examination shows moderate ascites. The patient has 3+ bilateral lower extremity pitting edema. Echocardiogram reveals left atrial enlargement with marked left ventricular hypertrophy and normal left ventricular ejection fraction. Complete blood count and basic metabolic panel are within normal limits. Endomyocardial biopsy findings are shown below. Which of the following is the most likely diagnosis?

Question

An 82-year-old man comes to the office due to progressive dyspnea and fatigue over the last year, which now limit his daily activities.  He has also noticed bilateral swelling of his feet.  The patient has hypertension, which is controlled with amlodipine.  His blood pressure is 122/72 mm Hg and pulse is 55/min.  Physical examination reveals elevated jugular venous pressure with rapid 'y' descent and a prominent S4.  Abdominal examination shows moderate ascites.  The patient has 3+ bilateral lower extremity pitting edema.  Echocardiogram reveals left atrial enlargement with marked left ventricular hypertrophy and normal left ventricular ejection fraction.  Complete blood count and basic metabolic panel are within normal limits.  Endomyocardial biopsy findings are shown below.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

11ec160b_38af_a903_9249_3144477a947c_MD0001_00 This patient's clinical presentation (eg, progressive exertional dyspnea, edema, ascites, elevated jugular venous pressure with rapid 'y' descent, prominent S4) and echocardiogram findings (eg, left atrial enlargement, left ventricular hypertrophy, normal ejection fraction) are consistent with diastolic heart failure due to restrictive cardiomyopathy. Restrictive cardiomyopathy can be idiopathic or caused by infiltrative diseases (eg, amyloidosis, sarcoidosis, hemochromatosis), radiation fibrosis, or endomyocardial fibrosis. Although most cases are associated with normal ventricular wall thickness, infiltrative conditions such as cardiac amyloidosis may lead to significant ventricular hypertrophy. Infiltrative diseases can also cause conduction system abnormalities (eg, bradycardia) that may ultimately require pacemaker implantation. Cardiac amyloidosis results from abnormal extracellular deposition of insoluble proteins such as monoclonal light chains (AL amyloidosis), mutated transthyretin (familial ATTR amyloidosis), or wild-type transthyretin (senile systemic amyloidosis) in myocardial tissue. Endomyocardial biopsy typically reveals cross-sections of normal myocardial cells with other areas of myocardium infiltrated by an amorphous and acellular pink material. Congo red stain classically shows apple-green birefringence under polarized light microscopy. (Choice A) Cardiac myxomas are the most common primary cardiac neoplasms, with approximately 80% originating in the left atrium. Left atrial myxomas can obstruct blood flow across the mitral valve, resulting in syncope and symptoms of heart failure. Endomyocardial biopsy typically reveals numerous bland stellate cells in a background of myxoid ground substance. (Choice B) Cardiac sarcoidosis can present with restrictive or dilated cardiomyopathy along with conduction defects and atrial or ventricular arrhythmias; sudden death can also occur. Microscopic examination of the myocardium reveals the presence of noncaseating granulomas containing giant cells. (Choice C) Chagas disease occurs secondary to Trypanosoma cruzi infection and is a common cause of myopericarditis and dilated cardiomyopathy in Latin America. Microscopic examination typically shows multiple parasitic protozoa within the myocardial fibers with a dense cellular infiltrate and myofiber destruction. (Choice D) Hemochromatosis leads to excessive iron deposition in the myocardium and can cause conduction abnormalities and restrictive or dilated cardiomyopathy. Endomyocardial biopsy typically reveals excessive iron deposition in the myocardium, which can be confirmed with Prussian blue staining. Educational objective: Restrictive cardiomyopathy can be caused by infiltrative diseases (eg, amyloidosis, sarcoidosis, hemochromatosis) and often results in diastolic heart failure due to ventricular hypertrophy with impaired ventricular filling. Cardiac amyloidosis is characterized histologically by areas of myocardium infiltrated by an amorphous and acellular pink material (amyloid).

An 82-Year-Old Man Comes to the Office Due to Progressive