LAUSR

A 63-year-old male with heart failure was admitted to our hospital. He had past medical history of bilateral carpal tunnel syndrome (CTS) in his early 50s. Cardiomegaly had been detected 6 years ago, and echocardiography revealed diffuse left ventricular (LV) hypertrophy. The patient had been observed by a family doctor until he gradually developed exertional dyspnea. He had no family history of cardiovascular diseases. Electrocardiogram showed complete left bundle branch block with atrial fibrillation. The same findings had been described in his past medical records in his early 50s. Echocardiography revealed increased LV wall thickness (interventricular septum 13.3 mm, posterior wall thickness 15.9 mm) with granular sparkling in the ventricular septum (Fig. 1). LV systolic function was diffusely reduced (ejection fraction 30–35%). Doppler echocardiography suggested diastolic dysfunction, as supported by an E-wave deceleration time of 242.0 ms and an E/e′ of 22.7 (E = 0.7 m/s, e′= 0.03 m/s). The right ventricle was enlarged, and mild tricuspid regurgitation was presented (estimated right ventricular pressure was 44 mmHg). A relative apical longitudinal strain was 1.7 with apical sparing. Serum laboratory testing showed amyloid A protein positive and BNP elevation (227.4 pg/mL). A technetium diphosphno-propanodicarboxylic acid (Tc-DPD) scintigram was also positive for myocardial uptake. We suspected this patient had cardiac amyloidosis. Bence-Jones protein and M-protein were negative. Endomyocardial biopsy confirmed transthyretin (TTR)-type cardiac amyloidosis (Fig. 1). In the biopsy specimen, Congo red staining revealed yellow–green birefringence of the deposits observed by polarizing microscope, and the deposits showed positive immunostaining for TTR. A hereditary form of TTR-derived amyloidosis was excluded by genetic analysis, and we made a diagnosis of wild-type TTR senile systemic amyloidosis (SSA). Conventional heart failure therapy (angiotensin-converting enzyme inhibitor, β-blocker, diuretics, and cardiac resynchronization therapy) was effective, and his heart failure condition is stable with oral medications. SSA is a form of amyloidosis associated with aging, and characterized by the deposition of amyloid fibrils derived from wild-type transthyretin (TTR) [1]. The diagnosis of SSA has become easier in recent years with advances in cardiac imaging (echocardiography, radioisotope, and magnetic resonance imaging) and more widespread use of genetic analysis [2,3]. Recent studies have indicated much younger SSA patients, with an onset around 50 years [4]. The present case had developed CTS in his early 50s, and then cardiomegaly was pointed out in his middle 50s, followed by progressive congestive heart failure in his 60s. This case sends us an educational message that SSA can progress even in the relatively young ages, hidden behind the asymptomatic diffuse LV hypertrophy.