<![CDATA[Background: ST-Elevation Myocardial Infarction (STEMI) is a cardiovascular emergency associated with high early mortality, particularly during the initial management phase in the emergency department (ED). Rapid and evidence-based nursing interventions are essential to improve patient outcomes. The MONA Plus nursing algorithm integrates early pharmacological therapy with critical nursing interventions in STEMI management. Purpose: To analyze the effectiveness of the MONA Plus nursing algorithm in reducing early mortality among STEMI patients in the emergency department. Method: This study used a quasi-experimental design with a posttest-only control group. A total of 40 STEMI patients were selected using sequential sampling and divided into an intervention group and a control group, each consisting of 20 participants at Dr. Soekardjo Regional General Hospital, Tasikmalaya, West Java, Indonesia. The intervention group received the MONA Plus nursing algorithm, while the control group received standard emergency management. Early mortality within 48 hours was analyzed using the Chi-square test with a significance level of p < 0.05. Results: Early mortality in the MONA Plus group was lower (10.0%) compared to the standard management group (35.0%). Statistical analysis showed a significant difference between the two groups (p = 0.041). Conclusion: The MONA Plus nursing algorithm was effective in reducing early mortality among STEMI patients and may be recommended as a standardized emergency nursing care protocol in Emergency Departments. Suggestion: The implementation of the MONA Plus nursing algorithm is recommended as a standard emergency department SOP, alongside continuous training for nurses, integration of evidence-based nursing into nursing curricula, and future studies involving larger samples and long-term outcomes. Keywords: Early Mortality; Emergency Unit; MONA Plus; Nursing Algorithm; STEMI Patients.]]>
