The interplay between atrial fibrillation and heart failure on long-term mortality and length of stay: Insights from the, United Kingdom ACALM registry.

Background: There is concern that the development of heart failure and atrial fibrillation has a detrimental influence on clinical outcomes. The aim of this study was to assess all-cause mortality and length of hospital stay in patients with chronic and new-onset concomitant AF and HF.

Methods: Using the ACALM registry, we analysed adults hospitalised between 2000 and 2013 with AF and HF and assessed prevalence, mortality and length of hospital stay. Patients with HF and/or AF at baseline (study-entry) were compared with patients who developed new-onset disease during follow-up.

Results: Of 929,552 patients, 31,695 (3.4%) were in AF without HF, 20,768 (2.2%) had HF in sinus rhythm, and 10,992 (1.2%) had HF in AF. Patients with HF in AF had the greatest all-cause mortality (70.8%), followed by HF in sinus rhythm (64.1%) and AF alone (45.1%, p<0.0001). Patients that developed new-onset AF, HF or both had significantly worse mortality (58.5%, 70.7% and 74.8% respectively) compared to those already with the condition at baseline (48.5%, 63.7% and 67.2% respectively, p<0.0001). Patients with HF in AF had the longest length of hospital stay (9.41days, 95% CI 8.90-9.92), followed by HF in sinus rhythm (7.67, 95% CI 7.34-8.00) and AF alone (6.05, 95% CI 5.78-6.31).

Conclusions: Patients with HF in AF are at a greater risk of mortality and longer hospital stay compared to patients without the combination. New-onset AF or HF is associated with significantly worse prognosis than long-standing disease.