Frontal T-P Angle: A Novel ECG Parameter for Predicting SYNTAX-1 and SYNTAX-2 Scores in Acute Non-ST-Segment Elevation Myocardial Infarction.

Highlights: Novel ECG Parameter: The frontal T-P angle (fT-Pa), derived from the difference between T-wave and P-wave axes, is introduced as a new predictor for coronary artery disease (CAD) complexity in acute NSTEMI patients.Strong Correlation with SYNTAX-2: fT-Pa showed a significant correlation with SYNTAX-2 scores (r = 0.229, *P* = 0.005), outperforming its association with SYNTAX-1, suggesting its utility in risk stratification.Predictive Cutoff Values: ROC analysis identified fT-Pa cutoffs of 36.5° (for SYNTAX-2 > 26.2) and 39.5° (for SYNTAX-1 > 22), offering practical thresholds for clinical use.Clinical Implications: fT-Pa provides a simple, reproducible tool to assess CAD severity even in patients with normal T-wave and P-wave axes, aiding early risk assessment in acute NSTEMI. 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.