Restrictive cardiomyopathy: The Daily PANCE Blueprint
A 68-year-old male presents with progressive dyspnea on exertion and bilateral lower extremity edema for the past 6 months. He reports orthopnea and occasional dizziness but denies chest pain. His past medical history includes carpal tunnel syndrome diagnosed 3 years ago and macroglossia noted on a recent dental visit. Physical examination reveals jugular venous distention, bibasilar crackles, hepatomegaly, and 2+ pitting edema to the mid-calf bilaterally. Cardiac examination demonstrates an S3 gallop and a grade II/VI systolic murmur at the apex. ECG shows low voltage QRS complexes and echocardiogram reveals biventricular wall thickening with normal systolic function, biatrial enlargement, and restrictive filling pattern. Which of the following is the most likely cause of this patient's restrictive cardiomyopathy?
A. Sarcoidosis
B. Scleroderma
C. Amyloidosis
D. Radiation-induced fibrosis
E. Hemochromatosis
Answer and topic summary
The answer is ANSWERHERE
Amyloidosis is the most common cause of restrictive cardiomyopathy. This patient’s presentation is classic for cardiac amyloidosis with progressive heart failure symptoms including dyspnea on exertion, orthopnea, jugular venous distention, and peripheral edema. The presence of associated systemic manifestations such as macroglossia and carpal tunnel syndrome are important clues pointing toward amyloidosis, particularly the AL (light chain) type. The echocardiographic findings of biventricular wall thickening with normal systolic function, biatrial enlargement, and restrictive filling pattern are characteristic of infiltrative cardiomyopathy. The low voltage QRS complexes on ECG despite ventricular wall thickening create a classic discrepancy that is highly suggestive of amyloid infiltration. Definitive diagnosis requires endomyocardial biopsy showing amyloid deposits that stain with Congo red and demonstrate apple-green birefringence under polarized light. Treatment depends on the type of amyloidosis, with AL amyloidosis typically managed with chemotherapy and autologous stem cell transplantation to eliminate the plasma cell clone producing the abnormal light chains.
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