A Stepwise ECG Algorithm to Resolve Identical Precordial Transition in Idiopathic Outflow Tract Ventricular Arrhythmias
Elena Krackhardt, Angeliki Darma, Alireza Sepehri Shamloo, Roman Michalski, Carmen Kolokowsky, Daniel Sedding, Arash AryaABSTRACT
Background
Accurate pre‐procedural differentiation of right (RVOT) versus left ventricular outflow tract (LVOT) origin in idiopathic outflow tract ventricular arrhythmias may facilitate procedural planning and mapping strategy. However, existing 12‐lead ECG criteria show variable performance and often fail to provide clear discrimination when the precordial transition during sinus rhythm and ventricular ectopy is identical.
Objective
To develop and evaluate a pragmatic, stepwise 12‐lead ECG algorithm integrating amplitude‐ and duration‐based parameters to discriminate RVOT from LVOT origin, with specific focus on identical precordial transitional patterns.
Methods
In this single‐center retrospective study, consecutive patients undergoing successful catheter ablation for idiopathic outflow tract ventricular arrhythmias were included. The reference standard was the documented site of successful ablation (RVOT vs. LVOT). A stepwise ECG algorithm was developed, incorporating morphology‐based criteria followed by a binary logistic regression model in patients with identical precordial transition. Diagnostic performance was assessed relative to the ablation site, and the regression model was internally validated using bootstrap resampling.
Results
A total of 133 patients were included (RVOT n = 76; LVOT n = 57). The 4‐step algorithm correctly classified 131 of 133 patients (98.5%). In the subgroup with identical transitions during sinus rhythm and PVCs ( n = 48), Step 4 demonstrated complete apparent classification, with an optimism‐corrected accuracy of 96.1% and an AUC of 0.958 after bootstrap validation. The estimated optimism‐corrected overall algorithm accuracy was 97%.
Conclusion
A probability‐based, stepwise ECG algorithm enables accurate discrimination between RVOT and LVOT origin, particularly in diagnostically challenging transitional patterns. If confirmed in external cohorts, this structured approach may support pre‐procedural localization and hypothesis‐driven mapping strategies in patients with idiopathic outflow tract ventricular arrhythmias.