Myocardial infarction: early bradyarrhythmia occurred.

Clinical bottom line (level 2b)

  1. Patients with acute myocardial infarction who were seen within 4 hours of symptom onset, were more likely to show a bradyarrhythmia than those seen more than 4 hours after symptom onset.
Adgey et al: Lancet 1968; : 1097-1101
Expires October 2003

The study

Prospective cohort study with objective outcomes, not adjusted for confounding factors, not validated in an independent set of patients.

Setting: mobile intensive care unit, UK (1966- 1968)

550 patients (aged mean 60 years, 73% male) acute myocardial infarction diagnosed by ECG evidence of recent infarction or sequential ST or T wave changes accompanied by significant and transient rise in serum-glutamic-oxalacetic-transaminase, or left-bundle-branch block with similar enzyme changes


100% followed for length of hospital stay
Outcomes studied:
  • bradycardia at initial examination when this was within 4 hours of symptoms onset sinus bradycardia, nodal bradycardia or atrioventricular block (second degree or block)
  • bradycardia at initial examination when this was more than 4 hours after symptom onset

    • The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    bradycardia at initial examination when this was within 4 hours of symptoms onset length of hospital stay 83/402 20.6%
    (16.9% to 24.9%)
    bradycardia at initial examination when this was more than 4 hours after symptom onset length of hospital stay 13/148 8.7%
    (4.2% to 13.3%)

    prognostic factor for
    bradycardia at initial examination when this was within 4 hours of symptoms onset     		time to outcome control rate (%) unadjusted OR
    (95% CI)    		 NNF+
    (95% CI)
    posterior myocardial infarction ? 35/233
    (20%)     		2.3
    (1.4 to 3.5)     		6
    (4 to 16)

    • Data in text and different tables do not correlate

    Comments

    1. How do the massive changes in management and diagnosis alter these findings?

    Citation

    1. Adgey AAJ, Geddes JS, Mulholland HC, et al: Incidence, significance, and management of early bradyarrhythmia complicating acute myocardial infarction. Lancet 1968; : 1097-1101
    Contributor: Clare Wotton and Bob Phillips, October 1999
    Reviewer:

    Clinical Question.
    Patient MI
    Intervention or Exposure time since onset of symptoms
    Outcome bradyarrhythmia