title: Clinical Characteristics, Management, and Outcomes of Acute Coronary Syndrome in Patients With Right Bundle Branch Block on Presentation.
abstract: We examined the relations between right bundle branch block (RBBB) and clinical characteristics, management, and outcomes among a broad spectrum of patients with acute coronary syndrome (ACS). Admission electrocardiograms of patients enrolled in the Global Registry of Acute Coronary Events (GRACE) electrocardiogram substudy and the Canadian ACS Registry I were analyzed independently at a blinded core laboratory. We performed multivariable logistic regression analysis to assess the independent prognostic significance of admission RBBB on in-hospital and 6-month mortality. Of 11,830 eligible patients with ACS (mean age 65; 66% non-ST-elevation ACS), 5% had RBBB. RBBB on admission was associated with older age, male sex, more cardiovascular risk factors, worse Killip class, and higher GRACE risk score (all p <0.01). Patients with RBBB less frequently received in-hospital cardiac catheterization, coronary revascularization, or reperfusion therapy (all p <0.05). The RBBB group had higher unadjusted in-hospital (8.8% vs 3.8%, p <0.001) and 6-month mortality rates (15.1% vs 7.6%, p <0.001). After adjusting for established prognostic factors in the GRACE risk score, RBBB was a significant independent predictor of in-hospital death (odds ratio 1.45, 95% CI 1.02 to 2.07, p = 0.039), but not cumulative 6-month mortality (odds ratio 1.29, 95% CI 0.95 to 1.74, p = 0.098). There was no significant interaction between RBBB and the type of ACS for either in-hospital or 6-month mortality (both p >0.50). In conclusion, across a spectrum of ACS, RBBB was associated with preexisting cardiovascular disease, high-risk clinical features, fewer cardiac interventions, and worse unadjusted outcomes. After adjusting for components of the GRACE risk score, RBBB was a significant independent predictor of early mortality.
authors.affiliation: Terrence Donnelly Heart Centre, Department of Medicine, St Michael's Hospital, Toronto, Canada; University of Toronto, Toronto, Canada.
authors.forename: William K
authors.initials: WK
authors.lastname: Chan
authors.affiliation: Terrence Donnelly Heart Centre, Department of Medicine, St Michael's Hospital, Toronto, Canada; University of Toronto, Toronto, Canada; Canadian Heart Research Centre, Toronto, Canada.
authors.forename: Shaun G
authors.initials: SG
authors.lastname: Goodman
authors.affiliation: Coronary Care Unit, Concord Hospital, Sydney, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Brieger
authors.affiliation: Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, United Kingdom.
authors.forename: Keith A A
authors.initials: KA
authors.lastname: Fox
authors.affiliation: Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom.
authors.forename: Chris P
authors.initials: CP
authors.lastname: Gale
authors.affiliation: Department of Cardiovascular Medicine, Department of Cardiovascular Medicine Flinders University, Adelaide, South Australia, Australia.
authors.forename: Derek P
authors.initials: DP
authors.lastname: Chew
authors.affiliation: University of Toronto, Toronto, Canada; Women's College Hospital, Toronto, Canada.
authors.forename: Jacob A
authors.initials: JA
authors.lastname: Udell
authors.affiliation: Hospital Universitario La Paz, Madrid, Spain.
authors.forename: Jose
authors.initials: J
authors.lastname: Lopez-Sendon
authors.affiliation: McGill University Health Centre, McGill University, Montreal, Canada.
authors.forename: Thao
authors.initials: T
authors.lastname: Huynh
authors.affiliation: University of Toronto, Toronto, Canada.
authors.forename: Raymond T
authors.initials: RT
authors.lastname: Yan
authors.affiliation: University of Toronto, Toronto, Canada; Sunnybrook Health Sciences Centre, Toronto, Canada.
authors.forename: Sheldon M
authors.initials: SM
authors.lastname: Singh
authors.affiliation: Terrence Donnelly Heart Centre, Department of Medicine, St Michael's Hospital, Toronto, Canada; University of Toronto, Toronto, Canada. Electronic address: yana@smh.ca.
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Yan
mesh_terms: D054058:Acute Coronary Syndrome / Q000150:complications / Q000453:epidemiology / Q000628:therapy*; D000368:Aged; D000369:Aged, 80 and over; D002037:Bundle-Branch Block / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology; D002170:Canada / Q000453:epidemiology; D019468:Disease Management; D004562:Electrocardiography; D005260:Female; D017052:Hospital Mortality / Q000639:trends; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011379:Prognosis; D012042:Registries; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D015996:Survival Rate / Q000639:trends