Background/Purpose:   Patients with lupus are at increased risk for cardiovascular disease. Previous studies on healthy adults showed that abnormalities detected on resting electrocardiography (ECG) are associated with an increased risk for subsequent cardiovascular (CV) events. These ECG-CV abnormalities are: ST-segment and/or T-wave abnormalities, left ventricular hypertrophy (LVH), left-axis deviation and bundle branch block (BBB).

We aimed to determine the prevalence of ECG-CV abnormalities in a cohort of lupus patients and to examine the factors associated with ECG-CV abnormalities.

Methods:   A standard digitally recorded 12-lead resting supine ECG was performed on consecutive patients attending the Lupus Clinic between October 2012-May 2014. Coded ECGs were reviewed and interpreted by a cardiologist using the Minnesota code classification system.

The frequency of the ECG-CV abnormalities was determined. In the univariate analysis normal ECG and ECG-CV abnormalities were compared (T-test and chi-squared test). Covariates with p<0.1 in addition to age, sex and ethnicity were evaluated with a stepwise logistic regression model to predict the ECG-CV abnormalities.

Results:   461 patients were studied. Of the 461 resting ECGs, 39.5% were abnormal: 7.6% axis deviation, 3.5% atrial enlargement, 11.3% arrhythmia and 6.7% pathological Q waves. ECG-CV abnormalities were present in 120 patients and included: ST-segment abnormalities and/or T-wave abnormalities  in 17.4%, LVH in 8.9%, left-axis deviation in 4.1% and BBB in 6.3%.

Of the 120 patients with ECG-CV abnormalities, 65.0% had 1 abnormality, 26.7% had 2, 6.7% had 3 and 1.7% had all 4 abnormalities.

In the univariate analysis, in the group of ECG-CV abnormalities, patients were older, had a longer lupus duration, higher damage index, higher cumulative dose of corticosteroids, history of previous CAD event, presence of Coombs’, La, LE cells, SCL70 and anti phospholipid lupus antibodies (table 1).

In the multivariate analysis, older age (OR =1.03; 95% CI: 1.01, 1.05; p=0.002), presence of damage (OR= 1.33; 95% CI: 1.17, 1.52; p<0.0001) and positive Coombs' (OR=2.37; 95% CI: 1.34, 4.21; p=0.003) were associated with ECG-CV abnormalities.

Conclusion:   Of 461 resting ECGs 39.5% were abnormal. 26% had ECG-CV abnormalities. Older age, damage and Coombs’ test were associated with ECG-CV abnormalities. These patients are at higher risk of developing CV events.

Table 1. Comparison of normal ECG and ECG-CV abnormalities

Other studied variables: AMS 3 years prior ECG, antimalarials and immunosuppressants ever @ ECG, Jo1, RNP, Ro, ANCA, anti dsDNA and ANA (p>0.05).