title: Assessment of Smith Algorithms for the Diagnosis of Acute Myocardial Infarction in the Presence of Left Bundle Branch Block.
abstract: OBJECTIVE
  Recently, a new electrocardiography algorithm has shown promising results for the the diagnosis of acute myocardial infarction in the presence of left bundle branch block (LBBB). We aimed to assess these new electrocardiography rules in a cohort of patients referred for primary percutaneous coronary intervention (pPCI).
  
  
  METHODS
  Retrospective observational cohort study that included all patients with suspected myocardial infarction and LBBB on the presenting electrocardiogram, referred for pPCI to 4 tertiary hospitals in Barcelona, Spain.
  
  
  RESULTS
  A total of 145 patients were included. Fifty four (37%) had an ST-segment elevation myocardial infarction (STEMI) equivalent. Among patients with STEMI, 25 (46%) presented in Killip class III or IV, and in-hospital mortality was 15%. Smith I and II rules performed better than Sgarbossa algorithms and showed good specificity (90% and 97%, respectively) but their sensitivity was 67% and 54%, respectively. In a strategy guided by Smith I or Smith II rules, 18 (33%) or 25 (46%) patients with STEMI would have not received a pPCI, respectively. Moreover, the severity and prognosis of STEMI patients was similar regardless of the positivity of Smith rules. Cardiac biomarkers were positive in 54% of non-STEMI patients, limiting their usefulness for initial diagnostic screening.
  
  
  CONCLUSIONS
  Diagnosis of STEMI in the presence of LBBB remains a challenge. Smith rules can be useful but are limited by suboptimal sensitivity. The search for new electrocardiography algorithms should be encouraged to avoid unnecessary aggressive treatments in the majority of patients, while providing timely reperfusion to a high-risk subgroup of patients.
authors.affiliation: Área del Corazón, Servicio de Cardiología, Hospital Universitario de Bellvitge, Barcelona, Spain. Electronic address: ayfanciu@hotmail.com.
authors.forename: Andrea
authors.initials: A
authors.lastname: Di Marco
authors.affiliation: Área del Corazón, Servicio de Cardiología, Hospital Universitario de Bellvitge, Barcelona, Spain.
authors.forename: Ignasi
authors.initials: I
authors.lastname: Anguera
authors.affiliation: Área del Corazón, Servicio de Cardiología, Hospital Universitario de Bellvitge, Barcelona, Spain.
authors.forename: Marcos
authors.initials: M
authors.lastname: Rodríguez
authors.affiliation: Servicio de Cardiología, Hospital de Sant Pau, Barcelona, Spain.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Sionis
authors.affiliation: Servicio de Cardiología, Hospital Universitario Germans Trias i Pujol, Badalona, Barcelona, Spain.
authors.forename: Antoni
authors.initials: A
authors.lastname: Bayes-Genis
authors.affiliation: Servicio de Cardiología, Hospital Clínic, Barcelona, Spain.
authors.forename: Jany
authors.initials: J
authors.lastname: Rodríguez
authors.affiliation: Área del Corazón, Servicio de Cardiología, Hospital Universitario de Bellvitge, Barcelona, Spain.
authors.forename: Albert
authors.initials: A
authors.lastname: Ariza-Solé
authors.affiliation: Área del Corazón, Servicio de Cardiología, Hospital Universitario de Bellvitge, Barcelona, Spain.
authors.forename: José Carlos
authors.initials: JC
authors.lastname: Sánchez-Salado
authors.affiliation: Servicio de Cardiología, Hospital de Sant Pau, Barcelona, Spain.
authors.forename: Mario
authors.initials: M
authors.lastname: Díaz-Nuila
authors.affiliation: Servicio de Cardiología, Hospital Clínic, Barcelona, Spain.
authors.forename: Mónica
authors.initials: M
authors.lastname: Masotti
authors.affiliation: Servicio de Cardiología, Hospital Universitario Germans Trias i Pujol, Badalona, Barcelona, Spain.
authors.forename: Roger
authors.initials: R
authors.lastname: Villuendas
authors.affiliation: Área del Corazón, Servicio de Cardiología, Hospital Universitario de Bellvitge, Barcelona, Spain.
authors.forename: Paolo
authors.initials: P
authors.lastname: Dallaglio
authors.affiliation: Área del Corazón, Servicio de Cardiología, Hospital Universitario de Bellvitge, Barcelona, Spain.
authors.forename: Joan Antoni
authors.initials: JA
authors.lastname: Gómez-Hospital
authors.affiliation: Área del Corazón, Servicio de Cardiología, Hospital Universitario de Bellvitge, Barcelona, Spain.
authors.forename: Ángel
authors.initials: Á
authors.lastname: Cequier
mesh_terms: D000368:Aged; D000465:Algorithms; D002037:Bundle-Branch Block / Q000150:complications* / Q000503:physiopathology; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D017052:Hospital Mortality / Q000639:trends; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D000072657:ST Elevation Myocardial Infarction / Q000150:complications / Q000175:diagnosis*; D013030:Spain / Q000453:epidemiology
keywords: Bloqueo de rama izquierda del haz de His; Electrocardiografía; Electrocardiography; Infarto agudo de miocardio; Intervención coronaria percutánea primaria; Left bundle branch block; Myocardial infarction; Primary percutaneous coronary intervention