Electrophysiological balance index as a marker of arrhythmic vulnerability in patients with bicuspid aortic valve

Background Bicuspid aortic valve (BAV) is the most common congenital cardiac anomaly and is traditionally associated with valvular dysfunction and progressive aortopathy. Beyond these structural manifestations, emerging evidence suggests that BAV may also predispose patients to electrical instability through myocardial remodeling, fibrosis, altered ventricular loading conditions, and autonomic imbalance. However, electrocardiographic markers capable of capturing arrhythmic vulnerability in this population remain poorly defined. The Index of Cardiac Electrophysiological Balance (iCEB), calculated as the ratio of ventricular repolarization to depolarization duration, integrates QT interval and QRS duration into a single parameter reflecting the dynamic balance between proarrhythmic and antiarrhythmic forces. Data regarding the clinical relevance of iCEB in patients with BAV are scarce. Purpose To evaluate the association between iCEB and arrhythmic events in patients with bicuspid aortic valve and to assess its diagnostic performance for arrhythmic risk stratification. Methods This case–control study included 92 patients with bicuspid aortic valve, divided into those with documented arrhythmic events (n=46) and arrhythmia-free controls (n=46). Clinical characteristics, valvular phenotype, and aortic dimensions were recorded. Standard 12-lead electrocardiograms obtained at baseline were analyzed by investigators blinded to clinical outcomes. QRS duration and QT interval were measured manually, and iCEB was calculated as QT/QRS. Corrected QT values were derived using Fridericia’s formula to minimize heart rate dependency. Multivariable logistic regression analysis was performed to identify independent predictors of arrhythmic events after adjustment for relevant clinical, valvular, and electrocardiographic variables. Discriminative performance of iCEB was assessed using receiver operating characteristic (ROC) curve analysis. Results Patients with arrhythmic events exhibited significantly prolonged QRS duration and QT interval, resulting in markedly higher iCEB values compared with arrhythmia-free controls (p<0.001). In multivariable logistic regression analysis, iCEB remained independently associated with arrhythmic risk, even after adjustment for age, heart rate, QTc interval, and QRS duration. ROC curve analysis demonstrated a moderate but clinically meaningful discriminative performance of iCEB for identifying arrhythmic events, with an area under the curve of 0.72, indicating acceptable diagnostic accuracy in this specific population. Conclusions In patients with bicuspid aortic valve, an increased index of cardiac electrophysiological balance is independently associated with arrhythmic events. iCEB provides an integrated, non-invasive electrocardiographic measure of electrical instability and may represent a practical tool for arrhythmic risk stratification in BAV patients, complementing traditional structural assessment.Characteristics of BAV PatientsROC Curve of iCEB