Comparison of Diltiazem and Metoprolol in the Management of Acute Atrial Fibrillation or Atrial Flutter
Condition: Heart Rate and Rhythm Disorders
MeSH terms: Atrial Fibrillation; Atrial Flutter
Intervention: Metoprolol; Diltiazem
Intervention MeSH terms: Metoprolol; Diltiazem
Phase: Phase 4
Study type: Interventional
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Enrollment: 54.0
Sex: All
Minimum age: 18 Years
Healthy volunteers: No
Keywords: metoprolol; diltiazem; heart rate

Summary:

      Acute atrial fibrillation is the most common sustained, clinically significant dysrhythmia
      encountered in the emergency department (ED) and the most common dysrhythmia treated by
      emergency physicians. Atrial flutter is less common than atrial fibrillation but its
      management in the ED is very similar, and the majority of patients with atrial flutter also
      have atrial fibrillation. Symptomatic relief and ventricular rate control are generally the
      primary therapeutic objectives in the ED management of acute atrial fibrillation and flutter
      (AFF). The need for swift, appropriate action by the emergency physician is highlighted by
      the fact that up to 18% of patients with AFF develop potentially life-threatening
      complications such as congestive heart failure, hypotension, ventricular ectopy, respiratory
      failure, angina and myocardial infarction.

      Both beta-blocking agents and calcium channel blockers are commonly used to treat AFF in the
      ED. Metoprolol is the most commonly used beta-blocker; and diltiazem is the most frequently
      used calcium channel antagonist.[8] Diltiazem was released by the FDA for treatment of AFF in
      1992. Shreck et al. were the first to demonstrate both the efficacy of diltiazem in the ED
      management of AFF with rapid rate and its clear superiority over the previously most commonly
      used pharmacologic agent, digoxin.

      To date, only one prospective, randomized trial has compared the effectiveness of a calcium
      channel blocker (diltiazem) with a beta-blocker (metoprolol) for rate control of AFF in the
      ED. Despite the relatively small sample size (n=20 in each group) the authors concluded that
      both pharmacologic agents were similarly effective. In order to test this finding, the
      investigators conducted a prospective comparison of metoprolol and diltiazem for the
      management of patients presenting to the ED with AFF with rapid ventricular rate.
    

Eligibility criteria:

        Inclusion Criteria:

        Eligible patients had to have a 12-lead electrocardiogram (ECG) showing atrial fibrillation
        or atrial flutter with a ventricular rate of greater than or equal to 120 beats per minute
        and a systolic blood pressure of greater than or equal to 90 mmHg.

        Exclusion Criteria:

        Patients were excluded if they had any of the following:

          -  a systolic blood pressure <90 mmHg, ventricular rate greater than or equal to 220
             beats per minute,

          -  QRS >0.100 seconds, 2nd or 3rd degree atrioventricular (AV) block,

          -  temperature >38.0 ˚C,

          -  acute ST elevation myocardial infarction,

          -  known history of New York Heart Association Class IV heart failure or

          -  active wheezing with a history of bronchial asthma or COPD.

        In addition, patients were excluded if there was:

          -  prehospital administration of diltiazem or any other AV nodal blockading agent,

          -  a history of cocaine or methamphetamine use in the previous 24 hours prior to arrival,

          -  a history of allergic reaction to diltiazem or metoprolol,

          -  a history of sick sinus or pre-excitation syndromes,

          -  a history of anemia with hemoglobin <11.0 g/dl,

          -  pregnancy or breastfeeding.