A 68-year-old man presents with progressive exertional dyspnea and bilateral ankle edema. Echo shows concentric LV wall thickening (IVS 16 mm) with a preserved EF of 55% and a restrictive filling pattern. ECG shows low voltage limb leads. He underwent bilateral carpal tunnel release five years ago. Which investigation is most likely to establish the diagnosis?

• A 99mTc-pyrophosphate (PYP) scintigraphy ✓
• B Coronary angiography
• C Transoesophageal echocardiography
• D Cardiac MRI with late gadolinium enhancement only

Explanation

The combination of concentric LV hypertrophy with discordantly low ECG voltage, diastolic dysfunction, and prior carpal tunnel syndrome strongly suggests cardiac amyloidosis, particularly wild-type transthyretin (ATTR) amyloidosis. Bone tracer scintigraphy with 99mTc-PYP avidly binds transthyretin deposits, and a grade 2-3 uptake with negative serum free light chains establishes ATTR without biopsy. Angiography and TOE add nothing diagnostic here, and MRI alone cannot identify the amyloid subtype.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.