Myocardial infarction: bradycardia: atropine improved vital signs

Clinical bottom line (level 4)

  1. Patients with bradycardia from a myocardial infarction who had atropine had a clinically significant increase in pulse and blood pressure.
  2. Most patients had a reduction in ventricular arrhythmias, and normalisation of blood pressure if they were hypotensive.
Scheinman et al: Circulation 1975; 52: 627-633
Expires October 2003

The study

Case series with unblinded, unobjective outcomes, not adjusted for confounding factors, not validated in an independent set of patients.

Setting:

56 patients (aged ?, ?% male) with a myocardial infarction (based on a compatible history, characteristic ECG and enzyme changes) who were bradycardic (pulse < 60 beats/min)

Excluded if
  • known sinus bradycardia
  • preterminal bradycardia or appearing during cardiopulmonary resuscitation
  • AV block present
  • on medication that might affect heart rate (digitalis or beta-blockers)


    • Patients received atropine 0.5 mg iv bolus.

    100% followed for minutes
    Outcomes studied:
  • decrease or abolition of ventricular arrhythmias
  • normalisation of pressure in hypotensive patients
  • adverse effects sustained sinus tachycardia, ventricular tachycardia or fibrillation, increased number of premature ventricular contractions, toxic psychosis

    • The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    decrease or abolition of ventricular arrhythmias minutes 27/31 87%
    (75% to 99%)
    normalisation of pressure in hypotensive patients minutes 15/17 88%
    (73% to 100%)
    adverse effects minutes 7/56 13%
    (3.8% to 21%)

    • Blood pressure rose by a mean of 20/11 mmHg.
    • Heart rate increased by a mean of 32 beats/min (95% CI: 26 to 37)

    Citation

    1. Scheinman MM, Thorburn D, Abbott JA: Use of atropine in patients with acute myocardial infarction and sinus bradycardia. Circulation 1975; 52: 627-633
    Contributor: Euan Ashley and Chris Ball, October 1999
    Reviewer: .

    Clinical Question.
    Patient myocardial infarction and bradycardia
    Intervention or Exposure atropine
    Outcome normotension, ventricular arrhythmias