An Afro-Caribbean patient with a thick heart.

A 68-year-old Afro-Caribbean woman presented with shortness of breath. Past history included bilateral carpal tunnel syndrome. Her father had died in his mid-40s, from heart failure. The patient was hypertensive (148/103mmHg) with mild peripheral oedema. An electrocardiogram showed atrial flutter at 160 beats/min, with low-normal limb lead voltage, and pre-cordial Q-waves (pseudo-infarction pattern). Echocardiography revealed a thickened left ventricular wall (18mm) and markedly reduced ejection fraction (25%) with moderate diastolic dysfunction. The patient was anticoagulated with warfarin and initially prescribed bisoprolol and digoxin for rate control. Inflammatory markers and serum amyloid-A levels were normal. Serum and urinary electrophoresis showed no evidence of paraprotein, with normal serum free light chains. Cardiac biomarkers were elevated, with an N-terminal brain natriuretic peptide of 446 pmol/l and a troponin T of 0.04 ng/ml. Further tests identified heterozygosity for the transthyretin gene mutation V122I (valine substituted for isoleucine at position 122). The bone tracer Tc-dicarboxypropane diphosphonate scan was markedly positive for cardiac based transthyretin amyloid involvement (Figure 1). An I labelled serum amyloid-P component scintigram showed no evidence of visceral amyloid deposition.