As transcatheter aortic valve implantation (TAVI) continues its rapid growth as a treatment approach for aortic stenosis, costs associated with TAVI and its burden to healthcare systems will assume greater importance. Patients undergoing TAVI between January 2012 and November 2017 in the Nationwide Readmission Database were identified. Trends in cause-specific readmissions were assessed using Poisson regression. Thirty-day TAVI cost burden (cost of index TAVI hospitalization plus total 30-day readmissions cost) was adjusted to 2017 U.S. dollars and trended over year from 2012 to 2017. Overall, 47,255 TAVI were included and 30-day readmissions declined from 20% to 12% (p<0.0001). Most common causes of readmission (heart failure, infection/sepsis, gastrointestinal causes, and respiratory) declined as well, except arrhythmia/heart block which increased (1.0% to 1.4%, p<0.0001). Cost of TAVI hospitalization ($52,024 to $44,110, p<0.0001) and 30-day cost burden ($54,122 to $45,252, p<0.0001) declined. While costs of an average readmission did not change ($9,734 to $10,068, p=0.06), cost burden of readmissions (per every TAVI performed) declined ($4,061 to $1,883, p<0.0001), including reductions in each of the top 5 causes except arrhythmia/heart block ($171 to $263, p=0.04). Index TAVI hospitalizations complicated by acute kidney injury, length of stay ≥5 days, low hospital procedural volume, and skilled nursing facility discharge were associated with increased odds of 30-day readmissions. In conclusion, the costs of index hospitalizations and 30-day cost burden for TAVI in the U.S. significantly declined from 2012-2017. However, readmissions due to arrhythmia/heart block and their associated costs increased. Continued strategies to prevent readmissions, especially those for conduction disturbances, are crucial in the efforts to optimize outcomes and costs with the ongoing expansion of TAVI.Copyright © 2020. Published by Elsevier Inc.