some bruising near my eye; area was a little tender; Afib started to act up; blacked out; Hit forehead on the door jamb; A spontaneous report was received from a consumer who was a 84-years-old, female patient who received Moderna's COVID-19 vaccine (mRNA-1273) and experienced area was a little tender, Afib started to act up, blacked out, hit forehead on the door jamb and had some bruising near eye.    The patient's medical history, as provided by the reporter, included atrial fibrillation with premature ventricular contractions (PVCs), and three cardioversions in the past 30 years. Concomitant medications reported included metoprolol, alprazolam, apixaban, amlodipine besylate, telmisartan, atorvastatin, ubidecarenone, multivitamin, vitamin B2, fish oil and cranberry extract.   On 14 Jan 2021, prior to the onset of the events, the patient received their first of two planned doses of mRNA-1273 intramuscularly in the left deltoid for prophylaxis of COVID-19 infection.   On 14 Jan 2021, after receiving the vaccine, the patient had no pain or soreness, but the area was a little tender if you pushed, and she waited one hour in the hospital afterwards.  As the patient was getting ready to leave, she felt a little lightheaded.  She was driven home, she ate lunch and then worked in the yard for a little bit. As she came inside, her Afib started to act up, she took an extra half of metoprolol, and had supper. She took half an alprazolam before going to bed. That night, as she got up to use the restroom, she had a strange feeling in her head like everything was going away. As she walked into the hallway, she blacked out and hit her forehead on the door jamb. Her forehead was all right but there was some bruising near her eye. She went back to bed and fell asleep.  On 15 Jan 2021, when the patient woke up in the morning, her rate was still acting up. At about 9:30am to 10:00am, everything improved, and her heart felt normal. Everything seemed to resolve in approximately 25 hours. Treatment also included acetaminophen/diphenhydramine (no details when it was taken). She contacted her cardiologist since receiving the first dose of the vaccine. The cardiologist encouraged her to take the second dose of vaccine with diphenhydramine and have someone stay with her that night in case something happened again. Consent given for Safety to follow up.  Action taken with mRNA-1273 in response to the events was not reported.   The outcome of events, Afib started to act up, blacked out and hit forehead on the door jamb, were resolved on 15 Jan 2021. The outcome of the events, area was a little tender and had some bruising near eye, were not provided.; Reporter's Comments: This case concerns a 84 year old female patient with medical history including atrial fibrillation with premature ventricular contractions (PVCs), and three cardioversions in the past 30 years. Concomitant medications reported included metoprolol, alprazolam, apixaban, amlodipine besylate, telmisartan, atorvastatin, ubidecarenone, multivitamin, vitamin B2, fish oil and cranberry extract.   She experienced serious unexpected events of Atrial fibrillation and Loss of consciousness and NS unexpected events of Contusion, Head injery and Vaccination site pain.  The events occurred after first dose of the study medication administration after she went back home.   Based on the current available information and temporal association between the use of the product and the start date of the events, a causal relationship cannot be excluded.  However, her medical history of heart condition and medication she took could remain a confounder.