ST-elevation myocardial infarction (STEMI); atrial fibrillation; This literature-non-study case was reported in a literature article and describes the occurrence of ACUTE MYOCARDIAL INFARCTION (ST-elevation myocardial infarction (STEMI)) and ATRIAL FIBRILLATION (atrial fibrillation) in a 37-year-old male patient who received mRNA-1273 (Spikevax) for COVID-19 vaccination.   The patient's past medical history included Aorta coarctation repair. Concurrent medical conditions included Hypertension and Bicuspid aortic valve.    On an unknown date, the patient received second dose of mRNA-1273 (Spikevax) (unknown route) 1 dosage form. On an unknown date,  after starting mRNA-1273 (Spikevax), the patient experienced ACUTE MYOCARDIAL INFARCTION (ST-elevation myocardial infarction (STEMI)) (seriousness criterion medically significant) and ATRIAL FIBRILLATION (atrial fibrillation) (seriousness criterion medically significant). The patient was treated with ASPIRIN [ACETYLSALICYLIC ACID] for STEMI, at an unspecified dose and frequency; METOPROLOL for STEMI, at an unspecified dose and frequency; ROSUVASTATIN for STEMI, at an unspecified dose and frequency; APIXABAN for STEMI, at an unspecified dose and frequency and LOSARTAN for STEMI, at an unspecified dose and frequency. At the time of the report, ACUTE MYOCARDIAL INFARCTION (ST-elevation myocardial infarction (STEMI)) and ATRIAL FIBRILLATION (atrial fibrillation) had resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Catheterisation cardiac: thrombus at the distal obtuse (abnormal) thrombus at the distal obtuse marginal branch trifurcation. On an unknown date, Echocardiogram: artery territory wall motion abnormalities (abnormal) right coronary and left circumflex artery territory wall motion abnormalities. On an unknown date, Electrocardiogram: inferoposterolateral infarction (abnormal) inferoposterolateral infarction. On an unknown date, Magnetic resonance imaging heart: abnormal (abnormal) late gadolinium enhancement in a vascular distribution consistent with MI in the inferior and inferolateral region. On an unknown date, Troponin I: 0.29ng/ml 0.29ng/mL.     For mRNA-1273 (Spikevax) (Unknown), the reporter considered ACUTE MYOCARDIAL INFARCTION (ST-elevation myocardial infarction (STEMI)) and ATRIAL FIBRILLATION (atrial fibrillation) to be related.    Self-limited exertional chest pain and shortness of breath ensued. His physician saw him 10 days later and does some lab test.  The ST-elevation myocardial infarction (STEMI) was thought to be related to the left circumflex artery thrombus, possibly embolic due to AF; the possibility of plaque rupture, thrombosis and distal embolization could not be excluded.  Concomitant medications were not reported.  Company Comment: This literature non-study case concerns a 37-year-old male patient with medical history of Aorta coarctation repair on an unknown date and concurrent Hypertension and Bicuspid aortic valve, who experienced the unexpected serious (medically significant) adverse events of special interest Acute myocardial infarction and Atrial fibrillation, that occurred on an unknown date after receiving the second dose of mRNA-1273 Vaccine. Patient noted malaise, body aches and later developed exertional chest pain and shortness of breath for which the following were performed: Cardiac catheterization: thrombus at the distal obtuse (abnormal) marginal branch trifurcation; Echocardiogram: artery territory wall motion abnormalities (abnormal) right coronary and left circumflex artery territory wall motion abnormalities; Electrocardiogram: infero-posterolateral infarction (abnormal); Magnetic resonance imaging heart: consistent with MI in the inferior and inferolateral region; and Troponin I: 0.29ng/ml 0.29ng/mL.Patient was treated with Aspirin, Metoprolol, Rosuvastatin, Apixaban and Losartan. The events resolved at the time of report. The medical history of Aorta coarctation repair and concurrent Hypertension and Bicuspid aortic valve remain as confounders. The benefit-risk relationship of mRNA-1273 Vaccine is not affected by this report. The events were considered related to the product per the reporter's assessment.; Sender's Comments: This literature non-study case concerns a 37-year-old male patient with medical history of Aorta coarctation repair on an unknown date and concurrent Hypertension and Bicuspid aortic valve, who experienced the unexpected serious (medically significant) adverse events of special interest Acute myocardial infarction and Atrial fibrillation, that occurred on an unknown date after receiving the second dose of mRNA-1273 Vaccine. Patient noted malaise, body aches and later developed exertional chest pain and shortness of breath for which the following were performed: Cardiac catheterization: thrombus at the distal obtuse (abnormal) marginal branch trifurcation; Echocardiogram: artery territory wall motion abnormalities (abnormal) right coronary and left circumflex artery territory wall motion abnormalities; Electrocardiogram: infero-posterolateral infarction (abnormal); Magnetic resonance imaging heart: consistent with MI in the inferior and inferolateral region; and Troponin I: 0.29ng/ml 0.29ng/mL.Patient was treated with Aspirin, Metoprolol, Rosuvastatin, Apixaban and Losartan. The events resolved at the time of report. The medical history of Aorta coarctation repair and concurrent Hypertension and Bicuspid aortic valve remain as confounders. The benefit-risk relationship of mRNA-1273 Vaccine is not affected by this report. The events were considered related to the product per the reporter's assessment.