Coronary artery disease: ECG exercise test was not very helpful at diagnosing in stable angina.

Clinical bottom line (level 1b-)

  1. A third of patients suspected of having coronary artery disease had it.
  2. In patients with stable angina, using equations of clinical, haemodynamic and computerised ST-segment analysis of the ECG exercise test, may help to rule out coronary artery disease better than ECG alone.
  3. In patients with stable angina, visual ST-segment analysis of the ECG exercise test was not very helpful in ruling out coronary artery disease.
Froelicher et al: Annals of Internal Medicine 1998; 128 (12): 965-974
Expires March 2003

The study

Setting: 12 university-affiliated Veterans Affairs Medical Centres, USA

814 patients (aged mean 58 years, 100% male) probable or definite stable angina

Excluded if
  • less than 28 years old
  • female
  • previous myocardial infarction
  • previous abnormal angiograms



    • Independent blinded reference standard, applied in all patients from a consecutive appropriate spectrum.
    Reference standard:
    • Coronary angiography- significant coronary artery disease was diagnosed if patients had at least one stenosis with narrowing of 50% or more was present in any artery or branch with a reference diameter of at least 1 mm.
    Diagnostic test: Exercise test performed with a ramp treadmill protocol. Two cardiologists read the ECGs. Data was interpreted using visual ST-segment analysis, and using increasingly complex equations.

    The evidence


    diagnostic test number of patients sensitivity for
    coronary artery disease
    (95% CI)    		 LR+ LR-
    visual ST-segment analysis 45.0%
    (32.0% to 58.0%)
    equation using clinical, haemodynamic and computerised St-segment variables 57.0%
    (48.0% to 67.0%)
    total 276

    • The less complex equations were less sensitive.

    Comments

    1. Increasing complexity in equations led to little improvement in the clinical utility of the system.

    Citation

    1. Froelicher VF, Lehmann KG, Thomas R, et al: The electrocardiographic exercise test in a population with reduced workup bias: Diagnostic performance, computerized interpretation, and multivariable prediction. Annals of Internal Medicine 1998; 128 (12): 965-974
    Contributor: Clare Wotton and Musab Hayatli, January 2000
    Reviewer: Dwight Peretz

    Clinical Question.
    Patient stable angina
    Intervention or Exposure scores, measurements and equations for or visual ST-segment measurements, for interpreting ECG exercise test
    Comparison coronary angiography
    Outcome coronary artery disease