Right Atrial Reservoir Strain Predicts Survival In Patients With Cardiac Amyloidosis

Introduction: Myofibril deposition in amyloidosis diffusely may affect cardiac structure and function. Right ventricular involvement has been associated with adverse clinical outcome. However, the utility of right atrial (RA) function assessment by echocardiographic strain imaging is unclear. Hypothesis: We hypothesize that right atrial stain has prognostic value in cardiac amyloidosis. Methods: We studied 121 consecutive patients with cardiac amyloidosis: 18% had transthyretin and 79% had light chain amyloidosis. Cardiac amyloidosis was either confirmed by endocardial biopsy (36%) or by a combination of non-cardiac tissue biopsy and proof of left ventricular hypertrophy (64%). Speckle tracking peak RA reservoir strain was assessed based on 6 segments from the apical 4-chamber view. All-cause mortality was tracked over a median of 5 years. Results: Echocardiographic peak longitudinal RA strain was feasible in 109 patients (90%). 60 CA patients died during follow-up period. Peak longitudinal RA strain was reduced in cardiac amyloidosis non-survivors (8.1%) in comparison to survivors (18.3%, p<0.01), showing RA involvement in cardiac amyloidosis. Peak RA strain was significantly associated with survival (using median 12.5%) (p<0.001). Low peak longitudinal RA strain was associated with a 3.3-fold increase in mortality risk (95% confidence interval: 1.83 - 5.96). Conclusions: Reduced peak longitudinal RA strain was significantly associated with survival in patients with cardiac amyloidosis. RA reservoir function assessed by strain appears to be useful as a new means to predict prognosis in cardiac amyloidosis patients and has promise for clinical application.