Cardiac amyloidosis

Abstract

Systemic amyloidosis comprises an uncommon group of disorders caused by the extracellular deposition of misfolded proteins in various organs. Cardiac amyloid deposition, causing an infiltrative/restrictive cardiomyopathy, is a frequent feature of amyloidosis and a major determinant of survival. It may be the presenting feature of the disease or may be identified while investigating a patient presenting with other organ involvement. The need for a high index of suspicion and the critical importance of precise biochemical typing of the amyloid deposits is paramount in light of recent therapeutic advances that can significantly improve prognosis. Most cases of cardiac amyloidosis are of either transthyretin type, which may be acquired in older individuals or inherited in younger patients, or acquired monoclonal immunoglobulin light chain (AL) type. This article aims to review recent developments in diagnosis and management of cardiac amyloidosis.

Keywords: AL amyloidosis; ATTR amyloidosis; CMR; cardiac amyloidosis; infiltrative cardiomyopathy.

Fig 1.

Congo red staining of myocardial tissue from two patients with amyloid cardiomyopathy. (a) Transthyretin type amyloidosis; (b) immunoglobulin light chain amyloidosis. Top panel = light microscopy; bottom panel = polarised light microscopy.

Fig 2.

Electrocardiogram of a patient with cardiac transthyretin type amyloidosis, showing sinus bradycardia with first degree atrioventricular block and small QRS voltages (defined as ≤6 mm height), predominantly in the limb leads.

Fig 3.

Echocardiography findings in a patient with cardiac transthyretin type amyloidosis. Parasternal long axis view (a) and four chamber view (b), showing concentric left ventricular hypertrophy; pulse-wave Doppler showing restrictive flow pattern of left ventricular inflow (c); and strain pattern characteristic of an infiltrative process (d).

Fig 4.

Cardiac magnetic resonance findings in a patient with cardiac immunoglobulin light chain amyloidosis. Four-chamber steady-state free precession cine (a); corresponding native T1 map (b); corresponding phase sensitive inversion recovery reconstruction late gadolinium enhancement image showing subendocardial late gadolinium enhancement (c); and corresponding extracellular volume map.

Fig 5.

Whole-body anterior ^99mTc-DPD scintigraphy (a) and single photon emission computerised tomography-CT (b) showing Perugini grade 2 abnormal uptake on a patient with cardiac transthyretin type amyloidosis.