Correct!
2. Infiltrative cardiomyopathy from amyloid disease
The echocardiogram shows thickening of both LV (>12 mm) and RV (>5 mm) walls, and enlarged atria. The patient was noted on echo in October 2017 to have grade 3 diastolic dysfunction all of which suggest a restrictive cardiomyopathy. Restrictive cardiomyopathy can be caused by infiltrative diseases such as amyloidosis or sarcoidosis, noninfiltrative causes such as diabetes, storage diseases such as hemochromatosis or endomyocardial disease such as carcinoid heart disease. Given this patient’s history of multiple myeloma, amyloid cardiomyopathy is most likely. Symptomatic amyloid is seen in about 15% of patients with multiple myeloma, and about 30% of patients with multiple myeloma have clinically occult amyloidosis (3).
Amyloid cardiomyopathy causes ventricular thickening from infiltrating amyloid fibrils, not myocyte hypertrophy. LV wall thickness greater than 12mm (6-10mm is normal) in the absence of hypertension should prompt work up for cardiac amyloid particularly with diastolic dysfunction. Characteristic ‘speckling’ pattern has low sensitivity and specificity. The LVEF is usually preserved, but the cardiac output is low due to decreased ventricular volume. This patient had a narrow pulse pressure on presentation likely from low stroke volume causing decreased cardiac output.
What is best method for diagnosing cardiac amyloid disease? (Click on the correct answer to proceed to the fifth of seven pages)