Non-ST Segment Elevation Acute Myocardial Infarction (NSTEMI) is one of the spectrums of Acute Coronary Syndrome (ACS) with a high mortality rate. Patients with NSTEMI require early risk stratification to define invasive strategy. Electrocardiography (ECG) has been proven useful for detecting cardiac abnormalities due to ACS. One of the ECG parameters used is the P wave peak time. The severity of myocardial ischemia or infarction is determined by the lesion of coronary artery and can be measured based on the SYNTAX score. This study aimed to determine the relationship between the P wave peak time and the SYNTAX score. Method: This is a cross-sectional study of NSTEMI patients who underwent angiography at the Adam Malik Hospital from July 2020 to June 2021. Measurements of P wave peak time on ECG were made in leads II and V1. The SYNTAX score was calculated based on the results of the angiography. Bivariate analysis was conducted to assess the correlation between the two variables. Then, ROC analysis was performed to assess the wave peak time as a predictor of coronary lesion severity. Result: Total subjects were 60 NSTEMI patients consist of 37 (61.66%) patients with severe coronary lesions (SYNTAX score < 23) and 23 (38.33%) patients with nonsevere coronary lesions (SYNTAX score  23). There is a moderate positive correlation between the P wave peak time and the SYNTAX score in lead II (r = 0.449; p < 0.001) and in lead V1 (r = 0.405; p = 0.001). Based on ROC analysis, the P wave peak time can predict the severity of coronary lesions with AUC = 0.71 in lead II and AUC = 0.68 in lead V1. Conclusion: The P wave peak time on the ECG has a correlation with the SYNTAX score and can predict the severity of coronary lesions in NSTEMI patients.

Keywords : NSTEMI, P Wave, SYNTAX Score, Coronary Lesion.