To the Editor Kalra et al1 used the Nationwide Inpatient Sample (NIS) to estimate the incidence of new-onset atrial fibrillation (AF) after transcatheter aortic valve implantation (TAVI) and surgical aortic valve replacement (AVR) and reported that 50% of patients develop AF after TAVI or AVR. We are concerned about the accuracy of the study results based on the methods used.