Trends, Burden, and Impact of Arrhythmias on Cardiac Transplant Recipients: A 16-year Nationwide Study

Orthotopic heart transplantation is the most effective long-term therapy for end-stage heart disease. Denervation with the loss of autonomic modulation, vasculopathy, utilization of immunosuppressant drugs, and allograft rejection may result in an increased prevalence of arrhythmias in transplanted hearts. We aim to describe the trends, distribution, and the clinical impact of arrhythmias in patients with transplanted hearts. We queried the National Inpatient Sample with administrative codes for cardiac transplant patients using procedure ICD-9-CM codes 37.5 and 33.6. Arrhythmias were extracted using validated ICD-9-CM codes. Statistical Analysis System (SAS) version 9.4 was used for analysis. There were a total of 30,020 hospitalizations of heart transplant recipients between 1999 and 2014 in the United States of which 1,6342 (54.4%) had an arrhythmia. The frequency of total arrhythmias increased from 53.6% (n=1,158) in 1999 to 67.3% (n=1,575) in 2014. Transplant patients with arrythmias was not associated with significantly higher inpatient mortality (7.72% vs 6.90%, P = 0.225). The most common arrythmia was atrial fibrillation ([AF]26.83%) followed by ventricular tachycardia (22.86%). Trends in mortality associated with arrhythmias following heart transplant has been decreasing from 12.3% in 1999 to 8.9% in 2014 (P = 0.04). Subgroup analysis of ventricular arrythmias (VA) following heart transplant were associated with increased mortality (8.61% vs 6.94%, P = 0.0229). Over half of patients develop 1 or more cardiac arrhythmia after heart transplant. There is an increasing secular trend in the frequency of arrhythmias post cardiac transplant with atrial fibrillation determined to be the most common arrhythmia.