Jiahao Zheng, Paul Knops, Mitchell M de Boer, Vehpi Yildirim, Mathijs S van Schie, Natasja M S de Groot
Focal activation patterns (FAPs) are frequently reported during atrial fibrillation (AF), yet their prevalence, stability, origin, and clinical significance vary considerably across studies. This variability largely reflects differences in mapping technologies, spatial resolution, analytical approaches, and criteria used to define FAPs. In this review, we summarize the methodologies used to identify FAPs, including spatial and temporal definitions, mapping strategies, and analytical techniques, and discuss how these methodological differences influence the interpretation of focal activity. We further examine evidence demonstrating that focal and rotational activation patterns may represent different manifestations of the same underlying conduction dynamics, depending on mapping resolution and analysis. Finally, we highlight current limitations and propose priorities for future research, including standardized identification criteria, cross-platform validation, and harmonized analytical workflows. Greater methodological consistency will be essential to accurately define the mechanistic and clinical significance of FAPs in AF.