title: Esmolol in acute ischemic syndromes.
abstract: BACKGROUND
  beta-Blockers have been shown to reduce both morbidity and mortality rates in patients with acute coronary syndromes. However, because of potential side effects, their use is limited in patients who might benefit the most from such therapy. It was thought that the use of an ultra-short-acting intravenous beta-blocker might produce similar results with fewer complications in those patients with relative contraindications to beta-blocker therapy.
  
  
  METHODS
  Accordingly, we evaluated the use of esmolol in patients with acute coronary syndromes and relative contraindication to beta-blocker therapy in a prospective randomized trial. One hundred eight patients at 21 sites received an infusion of intravenous esmolol or standard therapy on admission and were followed for 6 weeks from the day of admission. The primary efficacy outcome was a composite event consisting of any of the following that occurred during the index hospitalization: death, myocardial (re)infarction, recurrent ischemia, or arrhythmia as well as silent myocardial ischemia assessed by ambulatory electrocardiographic monitoring. Safety end points including hypotension, bradyarrhythmias, new or worsening congestive heart failure, and bronchospasm were also recorded.
  
  
  RESULTS
  Event rates for primary end points were similar in the 2 groups: death (2% in the standard care group vs 4% in the group receiving esmolol), myocardial (re)infarction (4% standard vs 7% esmolol), ischemia (12% vs 13%), arrhythmias (4% vs 2%), and silent ischemia (13% vs 15%). There was a higher incidence of transient hypotension in the group receiving esmolol (2% vs 16%), but all such events were noted to resolve after discontinuation of the esmolol infusion. There were no additional differences in safety end points: bradycardia (2% for those receiving standard care vs 9% receiving esmolol), new congestive heart failure (10% vs 16%), bronchospasm (0% vs 7%), and heart block (2% vs 2%).
  
  
  CONCLUSIONS
  The use of an ultra-short-acting beta-blocker such as esmolol might offer an alternative to patients with contraindications to standard beta-blocker therapy. Although this trial had limited power to detect safety and efficacy differences between the 2 therapies, it was observed that safety end points, which occurred during esmolol administration, resolved readily when the infusions were decreased or discontinued. Additional testing is needed to substantiate these findings.
authors.affiliation: St Louis University Health Sciences Center, St Louis, Mo 63110-1250, USA.
authors.forename: Rita G
authors.initials: RG
authors.lastname: Mitchell
authors.forename: Marcus F
authors.initials: MF
authors.lastname: Stoddard
authors.forename: Ori
authors.initials: O
authors.lastname: Ben-Yehuda
authors.forename: Kul B
authors.initials: KB
authors.lastname: Aggarwal
authors.forename: Kent S
authors.initials: KS
authors.lastname: Allenby
authors.forename: Raul A
authors.initials: RA
authors.lastname: Trillo
authors.forename: Ruth
authors.initials: R
authors.lastname: Loyd
authors.forename: Cheng-Tao
authors.initials: CT
authors.lastname: Chang
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Labovitz
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000789:Angina, Unstable / Q000188:drug therapy*; D002121:Calcium Channel Blockers / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy*; D018579:Patient Selection; D011412:Propanolamines / Q000627:therapeutic use*; D011446:Prospective Studies
chemical_list: D000319:Adrenergic beta-Antagonists; D002121:Calcium Channel Blockers; D011412:Propanolamines; C036604:esmolol