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Background: Cardiac involvement in systemic light-chain amyloidosis (AL) imparts an adverse impact on outcome. The left atrium (LA), by virtue of its anatomical location and muscular wall, is commonly affected by the amyloid process. Although LA infiltration by amyloid fibrils leads to a reduction in its pump function, the infiltration of the left ventricular (LV) myocardium results in diastolic dysfunction with subsequent increase in filling pressures and LA enlargement. Even though left atrial volume (LAV) is an independent prognostic marker in many cardiomyopathies, its value in amyloid heart disease remains to be determined. In addition, few data are available as to the prognostic value of LA function in systemic AL. Using cardiac magnetic resonance (CMR), the current study aims to assess the prognostic significance of the maximal LAV and total LA emptying fraction (LAEF) in patients with AL., Methods and Results: Fifty-four consecutive patients (age 66 ± 10 years, 59% males) with confirmed systemic AL and mean LV ejection fraction of 60 ± 12% underwent CMR. As compared with patients with no or minimal cardiac involvement (Mayo Clinic [MC] stage I), those at moderate and high risk (MC stages II and III) had significantly larger indexed maximal LAV (36 ± 15 vs. 46 ± 13 vs. 52 ± 19 mL/m(2), P = 0.03) and indexed minimal LAV (20 ± 6 vs. 34 ± 11 vs. 44 ± 17 mL/m(2), P < 0.001), lower LAEF (42 ± 9 vs. 26 ± 13 vs. 16 ± 9%, P < 0.0001) but similar LVEF. Furthermore, myocardial late gadolinium enhancement (LGE) was more frequent and significantly associated with lower LAEF. LAEF was also significantly lower in symptomatic (NHYA ≥ II, 22 ± 14%) as compared with asymptomatic patients (NYHA class I, 33 ± 13%, P = 0.006). Two-year survival rate was lower in patients with LAEF ≤ 16% as compared with those with LAEF > 16% (37 ± 11 vs. 94 ± 4%, P = 0.001). In multivariate analysis, lower LAEF remained independently associated with a higher risk of 2-year mortality (HR = 1.08 per 1% decrease, 95% CI: 1.02-1.15, P = 0.003)., Conclusion: In patients with systemic AL, LAEF as assessed by CMR is associated with NYHA functional class, MC stage, myocardial LGE and 2-year mortality., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.)

AL amyloidosis belongs to the group of conformational diseases. It is the most common type of amyloidosis with an estimated 500 new cases per year in France. It is due to a small and usually indolent plasma cell clone which synthesizes an unstable, misfolded monoclonal immunoglobulin light chain that is prone to aggregate and form amyloid fibrils. Non-invasive biopsy such as abdominal fat aspiration or minor salivary gland biopsy should be performed to confirm the diagnosis and if negative, involved tissues have to be examined. Clinical presentation is very diverse, as AL amyloidosis can affect almost any organ or tissue in the body, other than the brain. The kidney is the most frequent organ involved, whereas heart disease characterized by restrictive cardiomyopathy is the most severe. Early diagnosis, before advanced cardiomyopathy, is essential for improving outcome. The association of alkylating agent and high-dose dexamethasone is effective in almost two-thirds of patients. Combinations of proteasome inhibitors, dexamethasone, and alkylating agents achieve high response rates. Close monitoring of clonal and organ response is mandatory to guide therapy changes and duration. New treatments designed to eliminate amyloid deposits are under development., (Copyright © 2014 Société nationale française de médecine interne (SNFMI). Published by Elsevier SAS. All rights reserved.)