All-cause mortality (9 studies; n=2666) was rated as moderate quality evidence, no clear effect was shown with the confidence interval ranging from a decrease and increase in all-cause mortality. First heart-failure related admission was rated as moderate quality evidence (due to the indirectness of the outcome which did not report all-cause admissions as per the protocol) and showed no clinically important effect of beta-blockers (1 study; n=2616). Fatal and non-fatal stroke (1 study; n=2616) was rated as low quality evidence due to imprecision (as the confidence intervals surrounding the point estimate were wide). An absolute effect for this outcome could not be calculated as only the summary statistic was reported by the authors of the study with no report of event rates. No evidence was identified for the outcomes quality of life or improvement in NYHA class. Economic No relevant economic evaluations were identified. 6.2.2.6 Recommendations and link to evidence Recommendations No recommendation. Research recommendation What is the clinical and cost-effectiveness of beta blockers in patients with heart failure with reduced ejection fraction who are in atrial fibrillation? Chronic Heart Failure Treating Heart Failure NICE 2018. All rights reserved. Subject to Notice of rights. ISBN: 978-1-4731-3093-7 Relative values of different outcomes The committee considered the following outcomes as critical for this review: all-cause mortality, quality of life and all-cause hospitalisation. Data on all- cause mortality and all-cause hospitalisation were considered preferable to data limited to heart-failure related mortality and hospitalisations, as such data take into account the broader unintended consequences of the interventions (for example, an increase in mortality or hospitalisations due to adverse events). The committee agreed that cardiovascular mortality and heart failure related hospital admissions would be considered if the all-cause data was not available. 