Background

In non-valvular atrial fibrillation (NVAF) patients, congestive heart failure (CHF) confers an increased risk of stroke or systemic thromboembolism. This risk is present in both heart failure (HF) with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF). It is unclear if clinicians account for both types of CHF in their NVAF anticoagulation practices. Accordingly, we characterized current outpatient anticoagulation trends in NVAF patients with HFpEF compared to patients with HFrEF.

Methods

The outpatient NCDR PINNACLE-AF registry was analyzed to identify patients with NVAF and CHF. The study population was subdivided into HFpEF (ie, LVEF ≥ 40%) and HFrEF (LVEF < 40%). Anticoagulation rates by CHF group were compared and stratified by CHA₂ DS₂ -VASc score.

Results

A total of 340 127 patients with NVAF and CHF were identified, of whom 248 136 (73.0%) were classified as HFpEF and 91 991 (27.0%) as HFrEF. Patients with HFpEF had higher mean CHA₂ DS₂ -VASc scores and were more likely to be female, older, and have hypertension (P < 0.001). Unadjusted anticoagulation rates were significantly lower in patients with HFpEF compared to those with HFrEF (60.6% vs 64.2%, respectively). Lower rates of anticoagulation in the HFpEF group persisted after risk adjustment (RR: 0.93 [95% CI: 0.91, 0.94]). Stratification by CHA₂ DS₂ -VASc score demonstrated that lower rates of anticoagulation in patients with HFpEF persisted until a score of ≥5.

Conclusions

Patients with NVAF and HFpEF have significantly lower anticoagulation rates when compared to their HFrEF counterparts. These findings suggest a potential underappreciation of HFpEF as a risk factor in patients with NVAF.

Background

Although digoxin has long been used to treat atrial fibrillation (AF) and heart failure (HF), its safety remains controversial.

Objectives

This study sought to describe digoxin use over time in patients with AF who were stratified by the presence or absence of HF, to characterize the predictors of digoxin use and initiation, and to correlate digoxin use with outcomes.

Methods

Longitudinal patterns of digoxin use and its association with a variety of outcomes were assessed in a prospective outpatient registry conducted at 174 U.S. sites with enrollment from June 2010 to August 2011.

Results

Among 9,619 patients with AF and serial follow-up every 6 months for up to 3 years, 2,267 (23.6%) received digoxin at study enrollment, 681 (7.1%) were initiated on digoxin during follow-up, and 6,671 (69.4%) were never prescribed digoxin. After adjusting for other medications, heart rate was 72.9 beats/min among digoxin users and 71.5 beats/min among nonusers (p < 0.0001). Prevalent digoxin use at registry enrollment was not associated with subsequent onset of symptoms, hospitalization, or mortality (in patients with HF, adjusted hazard ratio [HR] for death: 1.04; without HF, HR: 1.22). Incident digoxin use during follow-up was not associated with subsequent death in patients with HF (propensity adjusted HR: 1.05), but was associated with subsequent death in those without HF (propensity adjusted HR: 1.99).

Conclusions

After adjustment for detailed clinical factors, digoxin use in registry patients with AF had a neutral association with outcomes under most circumstances. Because of the multiple conflicting observational reports about digoxin's safety and possible concerns in specific clinical situations, a large pragmatic trial of digoxin therapy in AF is needed.