Right Atrial Stiffness Assessed by Speckle‐Tracking Echocardiography: An Incremental Prognostic Indicator for Light‐Chain Cardiac Amyloidosis

BACKGROUND: Light chain cardiac amyloidosis (AL-CA) is an infiltrative cardiomyopathy characterized by the deposition of abnormally folded proteins in the myocardium and atrial walls. This study aims to evaluate right atrial (RA) stiffness-defined as the ratio of tricuspid E/e' (reflecting right ventricular diastolic function) to RA reservoir strain (right atrial reservoir strain (RASr), reflecting RA mechanical properties)-using speckle-tracking echocardiography, predicting the primary outcome in AL-CA, and assessing its incremental predictive value. METHODS: Seventy-eight patients (age: 59.40 ± 8.92 years; 60.3% male) with AL-CA and available follow-up data were studied by biopsy, noncardiac biopsy with supportive cardiac imaging. Clinical and routine echocardiographic data were retrospectively analyzed, with all-cause mortality followed during the period from September 2021 to September 2024. RESULTS: The median follow-up duration was 736 days (interquartile range: 375-1096 days). All-cause mortality occurred in 28 patients (36%). Restricted cubic spline (RCS) analysis identified a RA stiffness threshold of 0.9 as a robust outcome predictor (p < 0.001). Cox regression analysis showed RA stiffness (Tricuspid E/e'/RASr) was independently associated with adverse outcomes (adjusted hazard ratio = 4.33, p < 0.001). Kaplan-Meier survival curves demonstrated significant survival differences stratified by RA stiffness. Incorporating RA stiffness into the New York Heart Association(NYHA)functional class and Mayo 2012 models significantly improved their predictive accuracy (all p < 0.001). CONCLUSION: RA stiffness evaluated by speckle-tracking echocardiography has prognostic value in AL-CA, adding incremental predictive value to conventional staging models.