title: Efficacy and safety of out-of-hospital intravenous metoprolol administration in anterior ST-segment elevation acute myocardial infarction: insights from the METOCARD-CNIC trial.
abstract: OBJECTIVE
  We seek to examine the efficacy and safety of prereperfusion emergency medical services (EMS)-administered intravenous metoprolol in anterior ST-segment elevation myocardial infarction patients undergoing eventual primary angioplasty.
  
  
  METHODS
  This is a prespecified subgroup analysis of the Effect of Metoprolol in Cardioprotection During an Acute Myocardial Infarction trial population, who all eventually received oral metoprolol within 12 to 24 hours. We studied patients receiving intravenous metoprolol by EMS and compared them with others treated by EMS but not receiving intravenous metoprolol. Outcomes included infarct size and left ventricular ejection fraction on cardiac magnetic resonance imaging at 1 week, and safety by measuring the incidence of the predefined combined endpoint (composite of death, malignant ventricular arrhythmias, advanced atrioventricular block, cardiogenic shock, or reinfarction) within the first 24 hours.
  
  
  RESULTS
  From the total population of the trial (N=270), 147 patients (54%) were recruited during out-of-hospital assistance and transferred to the primary angioplasty center (74 intravenous metoprolol and 73 controls). Infarct size was smaller in patients receiving intravenous metoprolol compared with controls (23.4 [SD 15.0] versus 34.0 [SD 23.7] g; adjusted difference -11.4; 95% confidence interval [CI] -18.6 to -4.3). Left ventricular ejection fraction was higher in the intravenous metoprolol group (48.1% [SD 8.4%] versus 43.1% [SD 10.2%]; adjusted difference 5.0; 95% CI 1.6 to 8.4). Metoprolol administration did not increase the incidence of the prespecified safety combined endpoint: 6.8% versus 17.8% in controls (risk difference -11.1; 95% CI -21.5 to -0.6).
  
  
  CONCLUSIONS
  Out-of-hospital administration of intravenous metoprolol by EMS within 4.5 hours of symptom onset in our subjects reduced infarct size and improved left ventricular ejection fraction with no excess of adverse events during the first 24 hours.
authors.affiliation: Servicio de Urgencias Médicas de Madrid SUMMA112; Centro Nacional de Investigaciones Cardiovasculares CNIC, Madrid.
authors.forename: Alonso
authors.initials: A
authors.lastname: Mateos
authors.affiliation: Centro Nacional de Investigaciones Cardiovasculares CNIC, Madrid; Hospital Quirón, Universidad Europea Madrid; Hospital Puerta de Hierro, Madrid.
authors.forename: Inés
authors.initials: I
authors.lastname: García-Lunar
authors.affiliation: Centro Nacional de Investigaciones Cardiovasculares CNIC, Madrid; Hospital Universitario Central de Asturias, Oviedo.
authors.forename: José M
authors.initials: JM
authors.lastname: García-Ruiz
authors.affiliation: Centro Nacional de Investigaciones Cardiovasculares CNIC, Madrid; Hospital Quirón, Universidad Europea Madrid.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Pizarro
authors.affiliation: Centro Nacional de Investigaciones Cardiovasculares CNIC, Madrid; Hospital Clínico San Carlos, Madrid.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Fernández-Jiménez
authors.affiliation: Servicio de Urgencias Médicas de Madrid SUMMA112.
authors.forename: Pilar
authors.initials: P
authors.lastname: Huertas
authors.affiliation: Centro Nacional de Investigaciones Cardiovasculares CNIC, Madrid; Hospital Clinic, Barcelona.
authors.forename: Ana
authors.initials: A
authors.lastname: García-Álvarez
authors.affiliation: Centro Nacional de Investigaciones Cardiovasculares CNIC, Madrid; Hospital Universitario Montepríncipe, Madrid.
authors.forename: Leticia
authors.initials: L
authors.lastname: Fernández-Friera
authors.affiliation: Servicio de Urgencias Médicas de Madrid SUMMA112.
authors.forename: Jesús
authors.initials: J
authors.lastname: Bravo
authors.affiliation: Servicio de Emergencia Médica 061 Galicia Sur.
authors.forename: José
authors.initials: J
authors.lastname: Flores-Arias
authors.affiliation: Servicio de Emergencia Médica 061 Galicia Sur.
authors.forename: María V
authors.initials: MV
authors.lastname: Barreiro
authors.affiliation: Servicio de Emergencia Médica 061 Galicia Sur.
authors.forename: Luisa
authors.initials: L
authors.lastname: Chayán-Zas
authors.affiliation: Servicio de Asistencia Municipal de Urgencia y Rescate (SAMUR)-Protección Civil, Madrid.
authors.forename: Ervigio
authors.initials: E
authors.lastname: Corral
authors.affiliation: Centro Nacional de Investigaciones Cardiovasculares CNIC, Madrid; Mount Sinai School of Medicine, NY.
authors.forename: Valentín
authors.initials: V
authors.lastname: Fuster
authors.affiliation: Servicio de Urgencias Médicas de Madrid SUMMA112.
authors.forename: Vicente
authors.initials: V
authors.lastname: Sánchez-Brunete
authors.affiliation: Centro Nacional de Investigaciones Cardiovasculares CNIC, Madrid; Hospital Clínico San Carlos, Madrid. Electronic address: bibanez@cnic.es.
authors.forename: Borja
authors.initials: B
authors.lastname: Ibáñez
mesh_terms: D058671:Adrenergic beta-1 Receptor Antagonists / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D004632:Emergency Medical Services / Q000379:methods*; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008790:Metoprolol / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy*; D013318:Stroke Volume / Q000187:drug effects; D016896:Treatment Outcome
chemical_list: D058671:Adrenergic beta-1 Receptor Antagonists; D008790:Metoprolol