Clinical predictive scores for detection of sub-clinical atrial fibrillation after cryptogenic or embolic stroke of undetermined source: A brief systematic review

Subclinical atrial fibrillation (SAF) is the primary underlying cause of cryptogenic stroke (CS) or embolic stroke of undetermined source (ESUS), particularly in patients over 65 years of age. Therefore, it is strongly recommended screening for SAF in these patients. The development of tools designed to determine the priority of SAF screening is essential for optimizing the diagnostic workup. The aim of our study was to investigate the clinical predictive scores available for SAF detection in patients with CS or ESUS. We gathered data from articles published on the PubMed database from January 1, 2000, to January 31, 2023. Our search yielded eight scores for CS and three for ESUS. SAF diagnosis was established using various methods: 12-lead ECG or 24-h ECG monitoring during 1-year follow-up in three scores; 72-h non-implantable ECG monitoring in two scores; 2 or 3-week non-implantable ECG monitoring in three scores; and implantable ECG monitoring in one score. In two scores, ECG monitoring was performed using a non-implantable and/or implantable loop recorder. Overall, the rate of SAF detection was approximately 6% when using devices for monitoring lasting no more than 72 h and increased to nearly 22% employing 2 or 3-week non-implantable or implantable devices. SAF was defined differently in various scores; five scores considered any episode, even if shorter than 30 s, while six scores required episodes to last at least 30 s. Advanced age was included as a variable in 10 of 11 scores, whereas left atrial enlargement, premature atrial beats, and brain computed tomography characteristics were features in four scores. The area under the curve values of these scores ranged from 0.72 to 0.94. In conclusion, it is still challenging to put the currently available clinical scores to use due to a lack of validation. To provide more comprehensive guidance, it is essential to conduct large prospective multicenter trials in the future.