title: Achieving ventricular rate control using metoprolol in β-blocker-naive patients vs patients on chronic β-blocker therapy.
abstract: OBJECTIVE
  The objective of the study is to evaluate the difference in ventricular rate control using an intravenous (IV) metoprolol regimen commonly used in clinical practice in patients receiving chronic β-blocker therapy compared to patients considered β-blocker naive admitted to the emergency department (ED) for atrial fibrillation (AF) with rapid ventricular rate.
  
  
  METHODS
  A single-center retrospective cohort study of adult ED patients who were admitted with a rapid ventricular rate of 120 beats per minute (bpm) or greater and treated with IV metoprolol was performed. Rate control was defined as either a decrease in ventricular rate to less than 100 bpm or a 20% decrease in heart rate to less than 120 bpm after metoprolol administration. Patient demographics, differences in length of stay, and adverse events were recorded.
  
  
  RESULTS
  A total of 398 patients were included in the study, with 79.4% (n=316) receiving chronic β-blocker therapy. Patients considered to be β-blocker naive were more likely to achieve successful rate control with IV metoprolol compared to patients on chronic β-blocker therapy (56.1% vs 42.4%; P=.03). β-Blocker-naive status was associated with a shorter length of stay in comparison to patients receiving chronic β-blocker therapy (1.79 vs 2.64 days; P<.01).
  
  
  CONCLUSIONS
  Intravenous metoprolol for the treatment of atrial fibrillation with rapid ventricular rate was associated with a higher treatment response in patients considered β-blocker naive compared to patients receiving chronic β-blocker therapy.
authors.affiliation: Department of Pharmacy, Oregon Health & Science University, Portland, OR.
authors.forename: Patricia
authors.initials: P
authors.lastname: Kuang
authors.affiliation: Department of Pharmacy, Oregon Health & Science University, Portland, OR. Electronic address: mahn@ohsu.edu.
authors.forename: Nathan D
authors.initials: ND
authors.lastname: Mah
authors.affiliation: Department of Pharmacy, Oregon Health & Science University, Portland, OR.
authors.forename: Cassie A
authors.initials: CA
authors.lastname: Barton
authors.affiliation: Department of Pharmacy, Oregon Health & Science University, Portland, OR.
authors.forename: Andrea J
authors.initials: AJ
authors.lastname: Miura
authors.affiliation: Department of Pharmacy, Oregon Health & Science University, Portland, OR.
authors.forename: Laura R
authors.initials: LR
authors.lastname: Tanas
authors.affiliation: Department of Emergency Medicine, Oregon Health & Science University, Portland, OR.
authors.forename: Ran
authors.initials: R
authors.lastname: Ran
mesh_terms: D061605:Administration, Intravenous; D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000150:complications / Q000188:drug therapy*; D002318:Cardiovascular Diseases / Q000150:complications / Q000188:drug therapy; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007902:Length of Stay; D008297:Male; D008790:Metoprolol / Q000627:therapeutic use*; D008875:Middle Aged; D012189:Retrospective Studies; D017180:Tachycardia, Ventricular / Q000150:complications / Q000188:drug therapy*
chemical_list: D000319:Adrenergic beta-Antagonists; D008790:Metoprolol