Atrial fibrillation: Challenging the status quo: β-blockers for HF plus AF

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    Challenging the status quo: blockers for HF plus AFPaul Khairy and Denis Roy

    A new meta-analysis challenges the notion that -blockers improve survival in patients with heart failure (HF) and concomintant atrial fibrillation (AF). These results should be interpreted with caution. Although the mortality reduction conferred by -blockers was likely overestimated in the past, benefits should be expected in a sizeable proportion of patients with HF and AF.Khairy, P. & Roy, D. Nat. Rev. Cardiol. 11, 690692 (2014); published online 14 October 2014; doi:10.1038/nrcardio.2014.166

    Over the past 25years, the survival of patients with heart failure (HF) and reduced ejection fraction (HFrEF) has been prolonged, owing to advances in both pharmacological and device therapy, including angiotensinconvertingenzyme inhibitors, angiotensinreceptor blockers, blockers, mineralocorticoidreceptor antagonists, implantable cardioverterdefibrillators, cardiac resynchronization therapy, and left ventricular assist devices. The randomized controlled trials in which the efficacy of these therapies was first demonstrated have shaped current guidelines on HF management.1 In some instances, however, data from subsequent observational studies have contested the purported benefits of the treatment in particular patient subgroups and raised concerns over safety in the realworld setting.2,3 Blockers were developed in the 1960s by the Nobel Prize recipient, James Black, and have since become a staple in the management of HF.4 The benefits of blockers have largely gone unchallenged, but a new metaanalysis published in The Lancet calls into question their efficacy in reducing mortality in the subgroup of patients with HFrEF and coexisting atrial fibrillation (AF).5

    The BetaBlockers in Heart Failure Collaborative Group analysed individual patientlevel data from 10 major randomized clinical trials that compared blockers to placebo for the treatment of HF.5 This multinational consortium was created to determine the efficacy of blockers in understudied subgroups, including patients with concomitant AF.5,6 As expected, blocker administration was associated with

    a significant reduction in both allcause mortality (HR0.73, 95%CI 0.670.80, P

  • DECEMBER 2014 | VOLUME 11


    AF was electrocardiographically diagnosed in all patients, 44% exhibited normal sinus rhythm on their baseline ECG. A substantial proportion of patients with nonpermanent AF in Kotecha and colleagues study, therefore, likely escaped detection and were included in the sinusrhythm subgroup, which experienced an undisputed survival advantage from blockers.

    In a multivariate efficacy analysis of the AFCHF trial, blockers were associated with a 30% reduction in allcause mortality (HR0.70, 95%CI 0.550.90, P = 0.006) and a 34% reduction in cardiovascular mortality (HR0.66, 95%CI 0.490.87, P = 0.003).8 Furthermore, in a combined analysis of individual patientlevel data from both the AFCHF and AFFIRM trials, blockers were associated with a 35% reduction in cardiovascular mortality (HR0.65, 95%CI 0.460.92, P = 0.016) in patients with AF and a left ventricular ejection fraction


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