Relationships among achieved heart rate, β-blocker dose and long-term outcomes in patients with heart failure with atrial fibrillation

OBJECTIVE: Higher β-blocker dose and lower heart rate are associated with decreased mortality in patients with systolic heart failure (HF) and sinus rhythm. However, in the 30% of patients with HF with atrial fibrillation (AF), whether β-blocker dose or heart rate predict mortality is less clear. We assessed the association between β-blocker dose, heart rate and all-cause mortality in patients with HF and AF. METHODS: We performed a retrospective cohort study in 935 patients (60% men, mean age 74, 44.7% with reduced left ventricular ejection fraction (LVEF)) discharged with concurrent diagnoses of HF and AF. We used Cox models to test independent associations between higher versus lower predischarge heart rate (dichotomised at 70/min) and higher versus lower β-blocker dose (dichotomised at 50% of the evidence-based target), with the primary composite end point of mortality or cardiovascular rehospitalisation over a median of 2.9 years. All analyses were stratified by the presence of left ventricular systolic dysfunction (LVEF≤40%). RESULTS: After adjustment for covariates, neither β-blocker dose nor predischarge heart rate was associated with the primary composite end point. However, tachycardia at admission (heart rate >120/min) was associated with a reduced risk of the composite outcome in patients with both reduced LVEF (adjusted HR 0.67, 95% CI 0.52 to 0.88, p<0.01) and preserved LVEF (adjusted HR 0.79, 95% CI 0.64 to 0.98, p=0.04). CONCLUSIONS: We found no associations between predischarge heart rate or β-blocker dosage and clinical outcomes in patients with recent hospitalisations for HF and AF.