Crude death rates over a mean follow-up of 1♵ years (SD 1♱) were 16% (2237 of 13,945) in patients with sinus rhythm and 21% (633 of 3064) in patients with atrial fibrillation. The study is registered with, number NCT0083244, and PROSPERO, number CRD42014010012.ġ8,254 patients were assessed, and of these 13,946 (76%) had sinus rhythm and 3066 (17%) had atrial fibrillation at baseline. Outcome data were meta-analysed with an adjusted Cox proportional hazards regression. The primary outcome was all-cause mortality. The presence of sinus rhythm or atrial fibrillation was ascertained from the baseline electrocardiograph. We extracted individual-patient data from ten randomised controlled trials of the comparison of β blockers versus placebo in heart failure. We therefore meta-analysed individual-patient data to assess the efficacy of β blockers in patients with heart failure and sinus rhythm compared with atrial fibrillation. β blockers are indicated in patients with symptomatic heart failure with reduced ejection fraction however, the efficacy of these drugs in patients with concomitant atrial fibrillation is uncertain. 15 Norwich Medical School, University of East Anglia, Norwich, UK.Ītrial fibrillation and heart failure often coexist, causing substantial cardiovascular morbidity and mortality.14 Academic Cardiology, Castle Hill Hospital, Kingston upon Hull, UK.13 Division of Cardiology, University of Alberta, Edmonton, Canada.12 Department of Medical Sciences, Instituto di Ricovero e Cura a Carattere Scientifico San Raffaele Pisana, Rome, Italy.11 Nordic School of Public Health, Gothenburg, Sweden.10 Centre of Cardiovascular Research and Education in Therapeutics, Monash University, Melbourne, VIC, Australia Department of Cardiology, Oslo University Hospital, Oslo, Norway.9 University of Birmingham Centre for Cardiovascular Sciences, Birmingham, UK City Hospital, Sandwell and West Birmingham NHS Trust, Birmingham, UK Department of Cardiovascular Medicine, University Hospital Münster, Münster, Germany.8 Department of Cardiology, Sahlgrenska University Hospital, Gothenburg, Sweden.

7 Monash University, Melbourne, VIC, Australia Warwick University, Warwick, UK.

6 University of Birmingham Centre for Cardiovascular Sciences, Birmingham, UK City Hospital, Sandwell and West Birmingham NHS Trust, Birmingham, UK.

5 National Heart and Lung Institute, Royal Brompton and Harefield Hospitals, Imperial College, London, UK Hull York Medical School, University of Hull, Kingston upon Hull, UK.

4 Internal Medicine Department, Hospital Universitario Ramón y Cajal, Universidad de Alcalá, Madrid, Spain.

3 Centre of Cardiovascular Research and Education in Therapeutics, Monash University, Melbourne, VIC, Australia.Electronic address: 2 Centre for Statistics in Medicine, University of Oxford, Oxford, UK. 1 University of Birmingham Centre for Cardiovascular Sciences, Birmingham, UK Clinical Trials and Evaluation Unit, Royal Brompton and Harefield NHS Trust, London, UK Centre of Cardiovascular Research and Education in Therapeutics, Monash University, Melbourne, VIC, Australia.

To heart 2 dx plus