Left Ventricular Ejection Fraction and Incident Cardiac Conduction Dysfunction: Exploring the Mediating Effects of Electrophysiological Parameters.

BACKGROUND

Population-based evidence on the predictive role of left ventricular ejection fraction (LVEF) in incident Cardiac Conduction Dysfunction (CCD) and the mediating effects of electrophysiological parameters remains understudied. This study aimed to characterize the relationship between LVEF and incident CCD and explore the potential mediating effects of electrophysiological parameters.

METHODS

This prospective cohort study included 32,398 participants (96.6% White ethnicity) from the UK Biobank with analyzable LVEF and electrocardiogram data. Incident CCD was defined as the first occurrence of atrioventricular block, left bundle branch block, or other conduction disorders. Stepwise backward Cox regression and sensitivity analyses evaluated the association between LVEF and CCD. Additionally, mediation analysis was performed to examine QRS duration, PQ interval, and corrected QT interval as potential mediators.

RESULTS

During a mean follow-up of 6.96 ± 1.63 years, 484 incident CCD cases were identified. LVEF was an independent predictor of incident CCD, with each 1-standard deviation increase in LVEF associated with a 17% reduction in risk (adjusted hazard ratio, 0.83; 95% confidence interval, 0.77-0.89; p < 0.001). Sensitivity analyses across LVEF thresholds, competing risks, and exclusion of early events confirmed the robustness of these findings. Mediation analysis showed that PQ interval mediated 6% (p < 0.001), QRS duration mediated 17% (p < 0.001), and corrected QT interval mediated -3% (p = 0.002) of the total effect.

CONCLUSION

LVEF is independently associated with incident CCD, with electrophysiological parameters potentially explaining part of this association. These findings underscore the clinical relevance of myocardial mechano-electrical coupling in large-scale population settings.