Atrial Fibrillation; felt anxious; couldn't settle down; blood pressure was high; felt "funky"; This spontaneous case was reported by a consumer and describes the occurrence of ATRIAL FIBRILLATION (Atrial Fibrillation) in a 74-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 029K20A and 039K20A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     The patient's past medical history included Arrhythmia (heart was "shocked) in 2016, Pulmonary embolism (pulmonary embolisms were "drained) in 2016 and Cardioversion in May 2021. Concurrent medical conditions included Food allergy (Allergic to shrimp) and Sleep apnea.   On 16-Jan-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 12-Feb-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 12-Feb-2021,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced FEELING ABNORMAL (felt "funky"). On 25-Feb-2021, the patient experienced MOBILITY DECREASED (couldn't settle down) and HYPERTENSION (blood pressure was high). On an unknown date, the patient experienced ATRIAL FIBRILLATION (Atrial Fibrillation) (seriousness criterion medically significant). an unknown date, the patient experienced ANXIETY (felt anxious). The patient was treated with RIVAROXABAN (XARELTO) for Adverse event, at an unspecified dose and frequency and DOFETILIDE (TIKOSYN) for Adverse event, at an unspecified dose and frequency. At the time of the report, ATRIAL FIBRILLATION (Atrial Fibrillation), FEELING ABNORMAL (felt "funky"), ANXIETY (felt anxious), MOBILITY DECREASED (couldn't settle down) and HYPERTENSION (blood pressure was high) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 25-Feb-2021, Blood pressure measurement: high (High) High.         Concomitant medications were not included.  He reported that he went and bought a heart monitor and it showed he had Atrial Fibrillation. The caller mentioned he has an upcoming appointment on 29Nov2021 where he will be placed on Tikosyn and have a procedure done through the groin to send radio frequencies and zaps to the heart to treat Atrial Fibrillation  Company comment: This is a regulatory case concerning a 74 years old, male patient with clinical history of Heart arrhythmia and Pulmonary embolism who experienced the unexpected serious events of Atrial fibrillation (AESI, Arrhytmia) and other non-serious events. The events occurred 1 days after the second dose of Moderna Covid 19 vaccine The rechallenge is not applicable" as the events occurred after the second dose and no details were provided about the first dose The medical history of Heart arrhythmia and Pulmonary embolism remain as confounders. The benefit-risk relationship of Moderna Covid 19 vaccine is not affected by this report.; Sender's Comments: This is a regulatory case concerning a 74 years old, male patient with clinical history of Heart arrhythmia and Pulmonary embolism who experienced the unexpected serious events of Atrial fibrillation (AESI, Arrhytmia) and other non-serious events. The events occurred 1 days after the second dose of Moderna Covid 19 vaccine The rechallenge is not applicable" as the events occurred after the second dose and no details were provided about the first dose The medical history of Heart arrhythmia and Pulmonary embolism remain as confounders. The benefit-risk relationship of Moderna Covid 19 vaccine is not affected by this report.