In Reply We thank Leening and Ikram for their interest in our study on the occurrence of atrial fibrillation (AF) in a large cohort of elite athletes over a 20-year period.1 As they quite rightly state, incidence is “a measure to describe the occurrence of new outcomes among a defined group of previously outcome-free individuals in a certain amount of time.” In this respect, the AF cases we detected were most likely new cases of this condition over the study period, and thus we reported incident AF. Indeed, most athletes underwent yearly medical evaluations by the corresponding sport federation. Further, to screen for potential cases of incident AF, all athletes with 1 or more potentially suspicious cardiac signs (ie, severe bradycardia or frequent extrasystoles on resting/exercise electrocardiography) underwent 24-hour Holter monitoring in our center (with as many as 1505 assessments, as indicated in the article1).