This study evaluated the effectiveness of history, electrocardiogram, age, risk factors, and troponin (HEART), troponin-only Manchester acute coronary syndromes (T-MACS), and history and electrocardiogram-only Manchester acute coronary syndromes (HE-MACS) in diagnosing and managing acute coronary syndrome in patients presenting with chest pain in the emergency department. These scoring systems are crucial for risk stratification and the prediction of major adverse cardiac events (MACEs) and mortality within 30 days. A single-center prospective analytical study was conducted following the STROBE guidelines, with 560 patients presenting with chest pain or ischemic equivalent symptoms at the Ege University Faculty of Medicine Hospital from August 2020 to March 2021. The HEART, T-MACS, and HE-MACS scores were calculated for each patient, and their predictive values for MACE and mortality were analyzed using receiver operating characteristic analysis. The HEART score demonstrated an area under the curve (AUC) of 0.929 for predicting mortality, with 100% sensitivity and 81% specificity. It has been identified as the most reliable predictor of mortality. The T-MACS score showed an AUC of 0.875 for mortality prediction with 85.7% sensitivity and 83.9% specificity. It is particularly effective for high-risk patients, predicting 30-day MACE development rates, which is consistent with the literature. The HE-MACS score yielded an AUC of 0.729 for mortality prediction, with 71.4% sensitivity and 80.7% specificity. Although it effectively excludes MACE in very-low-risk patients, it is limited by its application to a highly isolated group. The discussion interprets the results and compares them with existing literature. The study confirms the high effectiveness of the HEART score in mortality risk assessment, the specificity of the T-MACS score for high-risk patients, and the utility of the HE-MACS score for excluding very-low-risk cases. The limitations of each scoring system are discussed and recommendations for their application in clinical practice are provided. The study concluded that selecting the most appropriate scoring system based on individual patient characteristics is essential for optimal patient management in the emergency department. For optimal patient management, it is essential to select the most appropriate scoring system based on the individual patient characteristics.