A 62-year-old man comes to the physician for a 3-month history of progressively worsening shortness of breath on exertion. Physical examination shows peripheral edema, jugular venous distention, and hepatomegaly. An S4 is auscultated. Transthoracic echo shows concentric left ventricular hypertrophy. Ejection fraction is 60%. A biopsy of myocardium is shown. Which of the following is the most likely underlying cause of this patient’s cardiac findings?
Antibodies against valvular tissue
Deposition of kappa light chains
Endocardial fibroelastosis
Giant cell myocarditis
Systolic dysfunction
