Atrial fibrillation or flutter on initial electrocardiogram is associated with worse outcomes in patients admitted for worsening heart failure with reduced ejection fraction: findings from the EVEREST Trial.

Background: Heart failure (HF) complicated by atrial fibrillation/flutter (AF/AFL) is associated with worse outcomes. However, the clinical profile and outcomes of patients following hospitalization for HF with AF/AFL on initial electrocardiogram (ECG) has not been well studied.

Methods: EVEREST was a randomized trial of vasopressin-2 receptor blockade, in addition to standard therapy, in 4133 patients hospitalized with HF with ejection fraction ≤40%. A post hoc analysis was performed comparing the clinical characteristics and outcomes [all-cause mortality and cardiovascular mortality/HF hospitalization] of patients with AF/AFL versus sinus rhythm (SR) on baseline ECG, which were centrally analyzed. Times to events were compared using log-rank tests and Cox regression models.

Results: Of the 4133 patients, 1195 (29%) were classified with AF/AFL and 2071(50%) with SR. The remaining patients (21%) were excluded because ECGs were unavailable (n = 106), rhythm was paced (n = 727), or junctional/other supraventricular (n = 34). AF/AFL patients were older, with increased weight, faster heart rate, higher blood urea nitrogen, and natriuretic peptide levels compared to SR patients. Anticoagulation was prescribed in 67% of AF/AFL patients on discharge. AF/AFL patients were less likely to receive β-blockers or angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (all P < .05). After risk adjustment, AF/AFL was associated with increased mortality (hazard ratio 1.23; 95% CI, 1.04-1.46) and cardiovascular mortality/HF hospitalization (hazard ratio 1.26; 95% CI, 1.07-1.47).

Conclusion: AF/AFL on initial ECG in patients hospitalized with HF with reduced ejection fraction is associated with lower use of evidence-based therapies and increased mortality and rehospitalization compared to patients in SR.