Hygrell T, Stridh M, Friberg L, et al. - This study was performed to construct the prevalence and prognostic implication of progressive supraventricular arrhythmias from frequent supraventricular ectopic complexes, isolated, in bi- or trigeminy, to supraventricular tachycardias with different characteristics. Participants registered 30-second intermittent ECG twice daily for two weeks in the STROKESTOP I mass-screening study for atrial fibrillation (AF) in 75- and 76-year olds in Sweden. Using an automated algorithm, the ECG-recordings from STROKESTOP I were re-assessed to detect individuals with frequent supraventricular ectopic complexes or runs. The outcomes revealed that the progression of atrial arrhythmias from supraventricular ectopic complexes to more AF-like episodes is correlated with development of AF. In individuals with frequent supraventricular activity, extended screening for AF should be considered, particularly in those with supraventricular tachycardias with AF characteristics.