Left ventricular fibrosis is strongly associated with atrial fibrillation (AF). However, the relationship between LV fibrosis and new-onset AF (NOAF) after ST-segment elevation myocardial infarction (STEMI) is currently unknown. This study was to investigate the relationship between different regions of ECV and NOAF during the acute phase of STEMI. ECV in integral (integral ECV), non-myocardial infarction region (NMI-ECV) and myocardial infarction region (MI-ECV) was obtained by CMR.

This retrospective study included patients diagnosed with STEMI at the Affiliated Hospital of Xuzhou Medical University. All patients underwent CMR during hospitalization, which included T1 mapping sequences. The blood sampling was collected within 24 hours of the CMR examination. Inclusion criteria: 1. Successful pPCI (TIMI flow ≥ 2) within 12 hours after symptom onset; 2. Admission to the cardiac care unit for continuous electrocardiogram (ECG) monitoring after pPCI. Exclusion criteria: 1. Poor image quality; 2. History of myocardial infarction; 3. History of atrial fibrillation; 4. Malignancy, or inflammatory disease; 5. Severe valvular heart disease; 6. Thyroid dysfunction. NOAF was defined as post-admission atrial fibrillation without a history of atrial fibrillation. ECG monitoring revealed a suspicious rhythm during admission, and an immediate 12-lead ECG confirmed NOAF. Infarct-related arteries (IRA) were recorded based on CAG findings. ECV in integral (integral ECV), non-myocardial infarction region (NMI-ECV) and myocardial infarction region (MI-ECV) was obtained by CMR.

Inclusion Criteria:

• Successful pPCI (TIMI flow ≥ 2) within 12 hours after symptom onset
• Admission to the cardiac care unit for continuous electrocardiogram (ECG) monitoring after pPCI

Exclusion Criteria:

• Poor image quality
• History of myocardial infarction
• History of atrial fibrillation
• Malignancy, or inflammatory disease
• Severe valvular heart disease
• Thyroid dysfunction

This retrospective study included patients diagnosed with STEMI at the Affiliated Hospital of Xuzhou Medical University from January 2020 to May 2024. All patients underwent CMR during hospitalization, which included T1 mapping sequences. The blood sampling was collected within 24 hours of the CMR examination. NOAF was defined as post-admission atrial fibrillation without a history of atrial fibrillation. ECV in integral (integral ECV), non-myocardial infarction region (NMI-ECV) and myocardial infarction region (MI-ECV) was obtained by CMR.