Trends and Outcomes of Atrial Fibrillation-Flutter Hospitalizations Among Heart Transplant Recipients (From the National Inpatient Sample) Dinesh Voruganti, MD a , Ghanshyam Shantha, MD, MPH b , Sushma Dugyala, MD c , Naga Venkata Krishna Pothineni, MD d , Kanishk Agnihotri, MD e , Behnam Bozorgnia, MD f , Aman Amanullah, MD f , Michael Giudici, MD a , and Alexandros Briasoulis, MD, PhD a, * Atrial fibrillation-flutter (AF) has been described in 10% to 24% of patients after heart transplant (HT). Data on AF hospitalizations after HT are limited to single-center experi- ences. To bridge this gap, we performed an analysis of admissions for AF in HT patients from the National Inpatient Sample (NIS) years 2000 to 2014. All hospitalizations with a primary diagnosis of 427.31 or 427.32 and V42.1 were used to identify hospitalizations with AF and previous HT respectively. Among a total of 211,961 HT related hospitaliza- tions, 1,304 (0.62%) (955 males, 349 females, mean age 59 years, median CHA 2 DS 2 Vasc score 2 [Interquartile range 1 to 3]) were admitted with a primary diagnosis AF. Most hos- pitalizations were nonelective (80.17%). In-hospital mortality was 2.3% and the mean length of stay (LOS) was 3.7 days. Among those patients who were discharged from hospi- tal, 85 % were discharged to home with self-care. Most commonly reported secondary diagnoses included hypertension (57.9%), diabetes (33%), renal failure (31.3%), and congestive heart failure (22%). The event rates for ischemic stroke and gastrointestinal bleeding in the same admission with the AF hospitalization were low (1.2% and 1.2% respectively). Cardioversion was performed in 37% and ablation in 11.2% of admissions. The adjusted median cost of hospitalization was $6478.7 (IQR $3561.8 to $12352.3) and did not change significantly during the study period. AF is a relatively infrequent cause of hospitalization among HT recipients. The number of hospitalizations, ablations, cardio- versions, disposition, LOS, and cost of hospitalization for AF remained stable during the study period. © 2019 Elsevier Inc. All rights reserved. (Am J Cardiol 2019;00:1-5) Heart transplant (HT) is the treatment of choice for refractory congestive heart failure with a median survival of »12 to 13 years and improved quality of life. 1 Though the outcomes in these patients have improved with the introduction of modern immunosuppressive treatments, patients continue to be at risk of developing complications during the post-transplant period. Approximately 10% to 24% of patients are at risk of arrhythmic complications such as atrial fibrillation-flutter (AF), 2-4 which are associ- ated with increased morbidity and mortality. Current litera- ture on AF in HT recipients is limited to single center studies and lacking in-hospital outcome data. We per- formed an analysis on the National Inpatient Sample (NIS) from 2000 to 2014 to understand the trends, in-hospital outcomes and related procedures of AF hospitalizations post-HT. Methods A detailed description of AF studies from the NIS data- base has been reported in the previous publications. 5,6 The NIS represents the largest, all-payer database of inpatient hospitalizations in the United States that is maintained by the Agency for Health Care Quality and Research (AHRQ). It includes a random 20% sample of all inpatient hospital- izations from 46 states in the United States from 1998 to 2014. Each observation in the NIS represents an individual hospitalization with a primary diagnosis, up to 29 secondary diagnoses, and up to 15 procedure codes. All discharge diagnoses and procedures were coded using the Interna- tional Classification of Disease, 9th revision, clinical modi- fication (ICD-9-CM) codes. Hospitalizations in the NIS reflect two different sam- pling strategies. Before 2012, the NIS included all dis- charges from a random sample of 20% of acute care hospitals in the United States, stratified by bed size, region, and location. Starting in 2012, the NIS included a random sample of 20% of discharges from all acute care hospitals in the United States; this effort reduced the margin of error by 50%, and national estimates decreased by 4.3%. From 1998 to 2011, discharge weights are provided by the AHRQ after a validation process, and they are used to calculate a Division of Cardiovascular Diseases, Section of Heart Failure and Transplant, University of Iowa Hospitals and Clinics, Iowa City, Iowa; b Division of Electrophysiology, University of Michigan, Ann Arbor, Michigan; c Department of Internal Medicine, University of Alabama, Tus- caloosa, Alabama; d Division of Electrophysiology, University of Pennsyl- vania, Philadelphia, Pennsylvania; e Division of Cardiology, University of Arkansas Medical Center, Little Rock, Arkansas; and f Division of Cardiol- ogy, Albert Einstein Medical Center, Philadelphia, Pennsylvania. Manu- script received August 17, 2019; revised manuscript received and accepted September 30, 2019. See page 5 for disclosure information. *Corresponding author: Tel: (319)-678-8418; fax: 319-353-6343. E-mail address: Alexandros-briasoulis@uiowa.edu (A. Briasoulis). www.ajconline.org 0002-9149/© 2019 Elsevier Inc. All rights reserved. https://doi.org/10.1016/j.amjcard.2019.09.038 ARTICLE IN PRESS