title: Incidence and clinical impact of right bundle branch block in patients with acute myocardial infarction: ST elevation myocardial infarction versus non-ST elevation myocardial infarction.
abstract: BACKGROUND
  Both left bundle branch block and right bundle branch block (RBBB) have been associated with increased inhospital and long-term mortality in patients with acute ST elevation myocardial infarction (STEMI). However, the prognostic role of RBBB in acute non-ST elevation myocardial infarction (NSTEMI) is not well known. Therefore, the aim of the study was to evaluate the incidence and clinical impact of RBBB in patients with NSTEMI compared to patients with STEMI.
  
  
  METHODS
  From the German prospective multicenter registry "Maximal Individual Therapy of Acute Myocardial Infarction" (MITRA PLUS), 6,403 consecutive patients with NSTEMI and 20,233 patients with STEMI were analyzed. Patients with left bundle branch block were excluded. The median follow-up time for NSTEMI was 378 days and for STEMI 479 days.
  
  
  RESULTS
  A total of 455 (7.1%) patients with NSTEMI and 894 (4.4%) patients with STEMI presented with RBBB on admission. In general, RBBB patients were older, more often had comorbidities, and less often received short-term inhospital treatment according to guidelines. In STEMI, RBBB patients had higher peak enzyme levels and lower left ventricular ejection fraction (LV-EF) than patients without BBB. Right bundle branch block in STEMI was associated with an increased inhospital and long-term mortality. In NSTEMI, however, peak enzyme levels and LV-EF were similar in both groups with and without RBBB. Right bundle branch block in NSTEMI was not independently associated with a worse outcome.
  
  
  CONCLUSIONS
  Unlike RBBB in STEMI, RBBB in NSTEMI is not an independent predictor of inhospital and long-term mortality.
authors.affiliation: Herzzentrum Ludwigshafen, Institut für Herzinfarktforschung Ludwigshafen an der Universität Heidelberg, Ludwigshafen, Germany. kleemann.thomas@web.de
authors.forename: Thomas
authors.initials: T
authors.lastname: Kleemann
authors.forename: Claus
authors.initials: C
authors.lastname: Juenger
authors.forename: Anselm Kai
authors.initials: AK
authors.lastname: Gitt
authors.forename: Rudolf
authors.initials: R
authors.lastname: Schiele
authors.forename: Steffen
authors.initials: S
authors.lastname: Schneider
authors.forename: Jochen
authors.initials: J
authors.lastname: Senges
authors.forename: Harald
authors.initials: H
authors.lastname: Darius
authors.forename: Karlheinz
authors.initials: K
authors.lastname: Seidl
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002037:Bundle-Branch Block / Q000453:epidemiology / Q000209:etiology*; D015897:Comorbidity; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D017052:Hospital Mortality; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000145:classification / Q000150:complications* / Q000401:mortality / Q000503:physiopathology; D019370:Observation; D011379:Prognosis; D020521:Stroke / Q000209:etiology; D013318:Stroke Volume