Background: Erectile dysfunction (ED) and coronary artery disease (CAD) frequently coexist, sharing common risk factors and pathophysiological mechanisms. The frontal QRS-T angle (fQRSTa), a novel electrocardiographic marker reflecting ventricular depolarization-repolarization heterogeneity, has been linked to adverse cardiac outcomes. However, the combined prognostic value of ED and fQRSTa in predicting CAD severity remains unexplored. The aim was to investigate whether the coexistence of ED and widened fQRSTa is associated with increased CAD severity, and to evaluate their individual and combined utility in identifying patients with advanced CAD.

Methods: This prospective observational study included 236 male patients undergoing first-time coronary angiography for suspected CAD. Patients were stratified into 4
groups based on ED status (International Index of Erectile Function–5 [IIEF-5] ≤21) and fQRSTa (cutoff: 52.5°). Coronary artery disease severity was assessed using the Gensini and SYNTAX scores. Hierarchical regression and correlation analyses were performed to evaluate associations.

Results: Erectile dysfunction prevalence was 62.7%, and patients with both ED and high fQRSTa exhibited significantly reduced ejection fraction and the highest Gensini
and SYNTAX scores (all P < .001). Regression analyses demonstrated that ED (β = 11.927, P = .009, 95% CI: 2.014-21.839), high fQRSTa (β = 9.906, P = .012, 95% CI: 2.710-22.523), and their interaction (β = 17.233, P = .028, 95% CI: 1.906-32.560) were independent predictors of higher Gensini scores after full adjustment. Similar results were observed for SYNTAX scores. A moderate inverse correlation was found between IIEF-5 and fQRSTa (r = −0.436, P < .001).

Conclusion: Erectile dysfunction and widened fQRSTa are independently and synergistically associated with more severe CAD. Their coexistence identifies a high-risk subgroup with pronounced angiographic abnormalities.