Automated echocardiographic measurements for longitudinal monitoring of ATTR cardiomyopathy: agreement and repeatability analysis

Detection of disease progression is key to personalize treatment strategies in transthyretin cardiomyopathy (ATTR-CM), particularly with emerging therapies. Echocardiography can detect subtle longitudinal changes but is limited by operator dependence. This study evaluates agreement and reproducibility of fully automated, AI-assisted echocardiographic measurements under real-world conditions. This retrospective study included 62 patients with ATTR-CM undergoing 178 serial annual echocardiograms assessed by a reference human reader, a second cardiologist (cardiologist 2), a novice reader, and a fully automated AI algorithm (Us2.ai). Interrater agreement was assessed using Bland-Altman analysis and intraclass correlation coefficients (ICCs). Intrarater variability for human readers was derived from repeated blinded measurements, with limits of agreement (LoA = mean difference ± 1.96 × SD) defining the minimal detectable change. AI repeatability was assessed using within-study automated pipeline variability across available acquisitions. AI showed moderate agreement with the reference human reader for IVSd and LVEDV (ICC 0.65 and 0.51), with biases of - 1.9 mm and - 39 mL, respectively. Interrater agreement between cardiologists was good (ICC 0.79 and 0.84) with minimal bias (- 0.2 mm and + 3 mL). Intrarater variability was moderate to excellent for both cardiologists (LoA 3.0 mm and 43 mL for the reference human reader; 2.7 mm and 44 mL for cardiologist 2). AI demonstrated comparable repeatability (LoA 3.6 mm and 37 mL), while the novice showed higher variability (5.1 mm and 61 mL). Fully automated measurements showed within-study variability of similar magnitude to the intrarater variability of experienced readers, although obtained with different experimental designs, supporting further prospective evaluation for serial assessment. Agreement in absolute terms was moderate for wall thickness and LV volumes, indicating expert oversight remains necessary in advanced disease.