Tehran University of Medical Sciences The Research in Heart Yield and Translational Medicine (RHYTHM) 3115-7270 20 1 2025 08 03 29 36 Erdoğan Sökmen Department of Cardiology, Kırsehir Ahi Evran Education and Research Hospital, Kırsehir, Turkey. Muhammet Ates Department of Cardiology, Kırsehir Ahi Evran Education and Research Hospital, Kırsehir, Turkey. 2024 09 14 2025 01 05 Background: Few studies have investigated P-wave and T-wave axes, most of which focus on mortality. The frontal T-P angle (fT-Pa) is a novel ECG-derived parameter of ventricular repolarization. We aimed to evaluate the association between fT-Pa and SYNTAX-1 (SS-1) and SYNTAX-2 (SS-2) scores in patients with acute non-ST-segment elevation myocardial infarction (ANSTEMI). Methods: This retrospective study included 158 ANSTEMI patients undergoing coronary angiography. The study population was stratified based on SS-1 (≤22 vs. >22) and SS-2 (≤26.2 vs. >26.2). The fT-Pa was calculated by subtracting the P-wave axis from the T-wave axis, both obtained from the ECG device's built-in software, and compared between groups. Results: fT-Pa showed significant correlations with age (r=0.242, P=0.003), SS-2 (r=0.229, P=0.005), and T-wave axis (r=–0.626, P<0.001). Both age and fT-Pa were significantly correlated with and predictive of SS-2 (β=0.679; OR, 0.700 [95% CI, 0.584 to 0.816]; P<0.001 for age) and (β=0.147; OR, 0.048 [95% CI, 0.012 to 0.085; P=0.010 for fT-Pa). ROC curve analysis identified an fT-Pa cutoff of 36.5 (64% sensitivity, 68% specificity; AUC, 0.674; P<0.001) for predicting SS-2 > 26.2, and a cutoff of 39.5 (70% sensitivity, 62% specificity; AUC, 0.692; P=0.010) for predicting SS-1>22. Conclusions: fT-Pa showed a stronger correlation and association with SS-2 than with SS-1. This parameter may serve as a simple, reproducible tool for predicting coronary artery disease complexity, even in patients with normal T-wave and P-wave axis ranges. https://rhythm.tums.ac.ir/index.php/jthc/article/view/2171 https://rhythm.tums.ac.ir/index.php/jthc/article/download/2171/1192