Chest pain and cardiac troponin flat curve: clinical differences in a cohort of patients with and without acute coronary syndrome

Introduction and Objectives Acute myocardial injury is defined by elevated cardiac troponin (cTn) above the 99th percentile with a dynamic change (∆>20%). When associated with a compatible clinical history, this suggests acute coronary syndrome (ACS). Some patients present with chest pain and initially elevated cTn but with ∆<20% (flat curve). This study analyzes their clinical characteristics. Patients and Methods We prospectively analyzed patients with suspected ACS and a cTn-flat curve (∆<20% in two serial high-sensitivity cTn-T determinations at 0/3 hours) from May 2023 to January 2025. Results 485 patients were included, mean age 75.6±12.3 years, 60.8% male. Their clinical characteristics are summarized in Table 1; 139 (28.6%) patients were admitted to Cardiology, 104 (21.4%) to other departments, and 242 (49.9%) were discharged directly from the emergency department. Coronary angiography was performed in 128 of the 243 patients admitted to hospitalization, revealing significant lesions in 96 (75%). Additionally, 14 patients were diagnosed with ACS through non-invasive tests. Conclusions in this group of patients cTn-flat curve did not exclude ACS; 110 cases (22.6%) had an ACS diagnosis. These patients had more males, higher cTn-T levels, more ST-T changes, wall motion abnormalities and ischemic symptoms but less atrial fibrillation.