Although numerous electrocardiographic (ECG) algorithms have been proposed for differentiating the origin of outflow tract ventricular arrhythmias, the best one has yet to be determined. The purpose of this research was to develop an ECG diagnosis model based on prior ECG algorithms. The aim of the study is to establish and evaluate the new index Y = -1.15 * TZ - 0.494 * (V2S/V3R) based on Transitional Zone (TZ) index and V2S/V3R index criteria. Methods: A cross - sectional descriptive study was conducted on 84 patients with the diagnosis of premature ventricular complex or ventricular tachycardia underwent catheter ablation at Vietnam National Heart Institute from August 2021 to August 2022. Results: The mean age was 50.4 ± 14.5 years old and the male/female ratio was 1/1.6. The percentage of premature ventricular complex and ventricular tachycardia was at 89.3% and 10.7%, respectively. The QRS complex morphology on the standard 12 - lead electrocardiography, including left bundle branch block pattern and inferior axis, implied the site of origin which was from ventricular outflow. The number of right ventricular outflow and left ventricular outflow patients was at 68 patients and 16 patients, respectively. The area under the curve for the ECG diagnostic model was 0.87, with a cut-off value of - 0.721 predicting a left ventricular outflow tract (LVOT) origin with a sensitivity of 85.3% and a specificity of 87.2%, which was greater than some previous ECG algorithms in this research. Conclusions: A highly reliable ECG diagnostic model for distinguishing between LVOT and right ventricular outflow tract origin was established.