Myocardial infarction: right bundle branch block increased risk of death at 1 year.

Clinical bottom line (level 1b)

  1. A fifth of patients who survive a myocardial infarction were dead at 1 year.
  2. Patients who had survived a myocardial infarction and had right bundle branch block, were at increased risk of death within 1 year.
Ricou et al: Journal of the American College of Cardiology 1991; 17: 858-863
Expires March 2003

The study

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

Setting: 6 centres, USA, Canada and Switzerland

932 patients (aged range 22 to 95 years; mean 63, 77% male) anterior myocardial infarction - Q waves >0.04 seconds or QS complex in the precordial leads and at least one of: chest pain or elevation of total serum creatinine kinase

Excluded if
  • died within the first 24 hours
  • evidence of other block in the absence of right bundle branch block



    • Factors studied:
  • 1 year mortality


    • Therapy not discussed.

    Multivariate analyses were performed to adjust for confounding factors.

    100% followed for 1 year
    Outcomes studied:
  • mortality at 1 year
  • mortality at 1 year without block
  • mortality at 1 year with right bundle branch block

    • The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    mortality at 1 year 1 year 200/932 22.2%
    (19.4% to 24.9%)
    mortality at 1 year without block 1 year 113/754 15.0%
    (12.4% to 17.5%)
    mortality at 1 year with right bundle branch block 1 year 87/178 48.9%
    (41.5% to 56.2%)

    • Age, history of congestive heart failure, history of MI, left ventricular failure and right bundle branch block were found to be adjusted confounding factors, but they were not reported in a standard form and therefore could not be used.

    Citation

    1. Ricou F, Nicod P, Gilpin E, et al: Influence of right bundle branch block on short- and long-term survival after acute anterior myocardial infarction. Journal of the American College of Cardiology 1991; 17: 858-863
    Contributor: Clare Wotton and Bob Phillips, October 1999
    Reviewer:

    Clinical Question.
    Patient acute anterior myocardial infarction
    Intervention or Exposure right bundle branch block
    Comparison no right bundle branch block
    Outcome mortality