Shedding Light on a Restrictive Diagnosis: Amyloid Cardiomyopathy

A 67-year-old African American woman with a history of end-stage renal disease (ESRD), hypertension, lumbar stenosis, and persistent atrial fibrillation (AF) with two ablations presents with progressive fatigue and dyspnea on exertion over the previous 6 months.

Her vital signs include blood pressure 111/68 mm Hg in the supine position, dropping to 85/62 mm Hg on standing, and an irregularly irregular rhythm at 88 bpm. Physical examination reveals a grade 2/6 systolic ejection murmur at the upper left sternal border, end-inspiratory crackles in the lower lung field, and 1+ bilateral edema. Electrocardiography shows AF with normal voltage. An echocardiogram obtained before the clinic visit is available (Videos 1, 2; Figures 1, 2). The serum free light chain (sFLC) kappa/lambda (κ/λ) ratio is 3.0 in the context of ESRD. Serum immunofixation electrophoresis (SIFE) and urine immunofixation electrophoresis (UIFE) show no monoclonal protein spike.

Video 1: Parasternal Long-Axis View

Video 1

Video 2: Apical Four-Chamber View

Video 2

Figure 1: Pulsed-Wave Doppler at Mitral Valve Inflow

Figure 1

Figure 2: "Bullseye" Map of Left Ventricular Longitudinal Strain Pattern

Figure 2

Which one of the following is the appropriate next step in diagnosis?

Show Answer