2018 年 82 巻 12 号 p. 3102-3103
An 80-year-old man had been clinically diagnosed with dilated cardiomyopathy for 5 years. He had no other comorbidities such as carpal tunnel syndrome and no electrocardiographic abnormalities such as pseudoinfarct pattern or left ventricular (LV) hypertrophy. Conventional echocardiography showed LV enlargement and markedly impaired contraction, without wall thickening or granular highly echogenic myocardium in both atria and ventricles (Figure A–C). Transmitral Doppler flow did not show a restrictive filling pattern (Figure D). Amyloid deposition was seen on endomyocardial biopsy specimen stained with hematoxylin-eosin, Masson trichrome and Congo red (Figure F-1–3). Further investigations including immunohistochemistry (Figure F-4) and genetic analysis led to a final diagnosis of wild-type transthyretin cardiac amyloidosis (ATTR-CA). Contrary to the similar clinical phenotype to dilated cardiomyopathy (excluding the histology), visual assessment of a bull’s eye plot of LV peak systolic longitudinal strain on speckle tracking echocardiography indicated a base-to-apex strain gradient, known as relative apical sparing (Figure E).1
(A–C) Although conventional echocardiography mimicked dilated cardiomyopathy (left ventricular [LV] end-diastolic dimension, 59 mm; LV ejection fraction, 25%; end-diastolic interventricular septal wall thickness, 10 mm; end-diastolic LV posterior wall thickness, 10 mm), (D) without granular highly echogenic myocardium or a restrictive transmitral filling pattern, (E) LV peak systolic longitudinal strain on 2-D speckle tracking echocardiography showed relative apical sparing. (F) Endomyocardial biopsy specimen stained with (F-1) hematoxylin-eosin, (F-2) Masson trichrome and (F-3) Congo red indicating amyloid deposition. (F-4) Immunohistochemistry led to the final diagnosis of transthyretin cardiac amyloidosis. Scale bars: (F-1a,2a) 100 μm; (F-1b,2b,3,4) 20 μm.
It has recently been reported that the clinical spectrum of ATTR-CA differs from the classic phenotype.2 Considering the heterogeneous form of CA, the relative apical sparing of longitudinal strain may be highly preserved, making it clinically useful in the evaluation of CA in patients with a wide range of cardiomyopathies.
The authors declare no conflicts of interest.
