Left and right axis deviation on ECG as predictors of long-term mortality

Background

Previous studies have linked electrocardiographic QRS axis deviation to increased mortality, but they have primarily focused on narrowly defined populations and rarely examined long-term mortality.

Objective

To evaluate the extent to which left axis deviation (LAD) and right axis deviation (RAD) are associated with 10-year all-cause mortality while controlling for demographic and electrocardiographic variables.

Methods

We conducted a retrospective cohort study of 1287 randomly selected ECGs performed at a single academic medical center. ECGs were categorized as normal axis, LAD, or RAD. Patients were followed for up to 10 years. Cox proportional hazards regression was used to estimate mortality risk, adjusting for demographic and electrocardiographic covariates.

Results

Most ECGs showed a normal axis (90.3 %), while 6.7 % had LAD and 3.0 % had RAD. Ten-year mortality was significantly higher in patients with LAD (65.1 %) and RAD (48.7 %) compared to those with a normal axis (28.4 %) (log-rank p < 0.001). In univariate analysis, LAD (hazard ratio [HR] = 3.04, 95 % CI: 2.29–4.04, p < 0.001) and RAD (HR = 2.16, 95 % CI: 1.36–3.43, p = 0.001) were associated with significantly increased mortality risk. In adjusted analyses, both LAD (HR = 1.58, 95 % CI: 1.15–2.18, p = 0.005) and RAD (HR = 2.17, 95 % CI: 1.32–3.58, p = 0.002) remained associated with increased mortality.

Conclusion

QRS axis deviation is a significant predictor of 10-year all-cause mortality and may serve as a useful tool for long-term mortality risk stratification.