Utility of left atrial strain in differentiating between cardiac amyloidosis and reablated atrial fibrillation

Abstract Introduction and Objectives Cardiac amyloidosis (AL) is a disease characterized by the abnormal accumulation of anomalous proteins in cardiac tissue, while atrial fibrillation (AF) is an exceedingly prevalent arrhythmia in the current population, often related to the amount of atrial fibrosis. The echocardiogram has emerged as a fundamental tool in the diagnosis and follow-up of these patients, and strain analysis techniques can provide highly useful additional information on cardiac function in these patients, especially in the early stages of the disease. We questioned whether it might be useful in differentiating between these two pathologies. Methods This retrospective analysis included adult patients who had undergone echocardiography at our center during the years 2023-2024. A total of 52 patients with a confirmed diagnosis of AL by transthyretin, confirmed by scintigraphy and/or biopsy, and another group of 47 patients with recurrent AF with at least two ablation procedures were included. Various left atrial strain values (Reservoir, Conduit, and Pump) were analyzed. Descriptive statistics were calculated for each group and segment, and the Mann-Whitney U test was used to compare the groups. Results Patients with AL showed significantly lower absolute strain values compared to patients with reablated AF in all three analyzed varieties (Reservoir, Conduit, and Pump) with p<0.01 for all comparisons. The mean strain in the reablated AF group was 17.42 for reservoir strain, -11.72 for conduit strain, and -6.33 for pump strain; while the mean in the AL group was 9.28, -6.93, and -3.10, respectively. Conclusions Our study found significant differences in left atrial strain values between patients with reablated AF and patients with transthyretin AL. These findings suggest that left atrial strain analysis could be useful in evaluating cardiac function, follow-up, and differential diagnosis between patients with AL and reablated AF, especially in the earlier stages of the disease, where it is more challenging to establish a reliable diagnosis. Atrial fibrillation Vs amyloidosis