Has the ClOpidogrel and Metoprolol in Myocardial Infarction Trial (COMMIT) of early β-blocker use in acute coronary syndromes impacted on clinical practice in Canada? Insights from the Global Registry of Acute Coronary Events (GRACE) Jeremy Edwards, MD, a,i Shaun G. Goodman, MD, MSc, a,b,i Raymond T. Yan, MD, b,i Robert C. Welsh, MD, c,i Jan M. Kornder, MD, d,i J. Paul DeYoung, MD, e,i Denis Chauret, MD, f,i Jean-Pierre Picard, MD, g,i Kim A. Eagle, MD, h,i and Andrew T. Yan, MD a,b ,i Ontario, Alberta, British Columbia, and Quebec, Canada; and Ann Arbor, MI Background The COMMIT/CCS-2 trial, published in 2005, demonstrated no net benefit of early β-blocker (BB) therapy in acute coronary syndromes (ACS). We sought to assess the short-term impact of this landmark trial by comparing the use of early BB therapy in patients with a broad spectrum of ACS before and after 2005. Methods Using data from the Global Registry of Acute Coronary Events and Canadian Registry of Acute Coronary Events, we compared the rates of BB use within the first 24 hours of presentation in the periods 1999 to 2005 and 2006 to 2008, after stratifying patients by the type of ACS (ST-segment elevation myocardial infarction [STEMI] and non–ST-segment elevation ACS [NSTEACS]) and clinical presentation. Results Of the 14,231 patients with ACS, 77.7% received BB therapy within 24 hours of presentation (78.5% and 77.4% in the STEMI and NSTEACS groups, respectively). The early use of BB declined in the STEMI group (80.3% to 76.7%, P = .005) but increased in the NSTEACS group (75.4% to 78.9%, P b .001) after 2005. Long-term BB use, higher systolic blood pressure, and higher heart rate were independent predictors of early BB use. Conversely, patients who were female, older, Killip class N1, and had cardiac arrest at presentation were less likely to receive early BB. Multivariable analysis showed a trend toward lower use of BB among patients with STEMI (adjusted odds ratio 0.76, 95% CI 0.57-1.00, P = .055) and a trend toward more frequent BB use among patients with NSTEACS (adjusted odds ratio 1.22, 95% CI 0.96-1.55, P = .11) after 2005. The temporal trends in the early use of BB differed between patients with STEMI and patients with NSTEACS (P for interaction with period b.001). Conclusions Most patients with STEMI or NSTEACS were treated with early BB therapy. In accordance with the COMMMIT/CCS-2 trial, patients with lower systolic blood pressure and higher Killip class in the “real world” less frequently received early BB therapy. Since the publication of COMMIT/CCS-2, there has been no significant change in the use of BB in patients with STEMI or NSTEACS after controlling for their clinical characteristics. (Am Heart J 2011;161:291-7.) β-Blocker (BB) therapy has been used in the manage- ment of acute coronary syndromes (ACS) for decades. The proposed mechanisms of benefit of BBs in the setting of acute myocardial infarction include decreased myo- cardial oxygen consumption due to effects on heart rate (HR), contractility, and afterload; antiarrhythmic effects; and improved myocardial oxygen supply secondary to a prolonged diastolic filling interval. 1 Long-term beneficial effects include protection against adverse remodeling and declining ventricular function. 2,3 In late 2005, the COMMIT/CCS-2 trial was published. 4 Largely in response to the results of COMMIT/CCS-2, the American College of Cardiology (ACC) and the American Heart Association (AHA) updated their guidelines on the From the a Division of Cardiology, Terrence Donnelly Heart Centre, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada, b Canadian Heart Research Centre, Toronto, Ontario, Canada, c Mazankowksi Alberta Heart Institute, Edmonton, Alberta, Canada, d Surrey Memorial Hospital, Surrey, British Columbia, Canada, e Cornwall Community Hospital, Cornwall, Ontario, Canada, f University of Ottawa, Ottawa, Ontario, Canada, g Hopital Hotel-Dieu de Sorel, Sorel-Tracy, Quebec, Canada, and h University of Michigan Health System, Ann Arbor, MI. i For the Canadian Global Registry of Acute Coronary Events (GRACE) and Canadian Registry of Acute Coronary Events (CANRACE) investigators. Submitted March 3, 2010; accepted October 18, 2010. Reprint requests: Andrew T. Yan, MD, Division of Cardiology, St. Michael's Hospital, 30 Bond Street, Room 6-030 Queen, Toronto, Ontario, Canada M5B 1W8. E-mail: yana@smh.ca 0002-8703/$ - see front matter © 2011, Mosby, Inc. All rights reserved. doi:10.1016/j.ahj.2010.10.034