Can Single-Lead Computerized Electrocardiography Predict Myocardial Infarction in Young and Middle-Aged Men? The Tromsø Study

Abstract

Background

In epidemiological studies, the electrocardiogram has often been interpreted by means of a categorical classification. Computerized recording offers the possibility of analysing electrocardiographic measurements as continuous variables.

Objective

To test the hypothesis that duration of QRS complex and T-wave inversion would be independent predictors of myocardial infarction.

Methods

In a population-based study, we prospectively investigated the risk of developing myocardial infarction according to duration of QRS complex and peak-to-peak T-wave amplitude measured from lead I of the 12-lead electrocardiogram by computerized electrocardiography. In total 6628 men aged 25–61 years who had not previously suffered a myocardial infarction were followed up for 3.9 years.

Results

Eighty-two first myocardial infarctions (55 non-fatal and 24 fatal myocardial infarctions and three sudden deaths) were identified. The risk of myocardial infarction increased with duration of QRS complex and with decreasing T-wave amplitude. A proportional hazards model with adjustment for possible confounders yielded a relative risk of myocardial infarction of 3.74 (P for linear trend 0.015) for duration of QRS complex ≥ 120 ms compared with duration of QRS complex < 80 ms. The multivariate relative risk for T-wave amplitude ≥ 0.35 mV compared with T-wave amplitude < 0.20 mV was 0.55 (P for linear trend 0.036). When both duration of QRS complex and T-wave amplitude were included in the multivariate model, T-wave amplitude retained its predictive power, whereas duration of QRS complex became marginally no longer significant (P = 0.067).

Conclusions

Peak-to-peak T-wave amplitude from lead I is an independent predictor of myocardial infarction in men who have not previously suffered a myocardial infarction. Greater duration of QRS complex clearly indicates a higher risk of myocardial infarction. However, when T-wave amplitude is included as a covariate, the predictive power of duration of QRS complex does not remain significant Single-lead electrocardiography is a feasible method for improving the assessment of the relative risk of myocardial infarction.