Atrial fibrillation; hurts when puts out laterally; numbness left side of face; blood pressure dropped; stomach(muscle) pains; weakness in the left arm; to whole left side of body being in pain; pain in arm went through arm to neck; burst of pain to neck; pain left side of face; alopecia spot/hair fell out; feeling lightheaded; sever vertigo.; headache; This spontaneous case was reported by a consumer and describes the occurrence of ATRIAL FIBRILLATION (Atrial fibrillation) in a 51-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 030B21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Hypertension. Concomitant products included CARVEDILOL for Hypertension.    On 10-Apr-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 10-Apr-2021, the patient experienced DIZZINESS (feeling lightheaded), VERTIGO (sever vertigo.) and HEADACHE (headache). On 14-Apr-2021, the patient experienced ALOPECIA (alopecia spot/hair fell out). On 26-Apr-2021, the patient experienced PAIN IN EXTREMITY (pain in arm went through arm to neck), NECK PAIN (burst of pain to neck) and FACIAL PAIN (pain left side of face). On an unknown date, the patient experienced ATRIAL FIBRILLATION (Atrial fibrillation) (seriousness criterion medically significant), PAIN (hurts when puts out laterally), HYPOAESTHESIA (numbness left side of face), BLOOD PRESSURE DECREASED (blood pressure dropped), MYALGIA (stomach(muscle) pains), ASTHENIA (weakness in the left arm) and MYALGIA (to whole left side of body being in pain). The patient was treated with METOPROLOL for Atrial fibrillation, at an unspecified dose and frequency and APIXABAN (ELIQUIS) for Atrial fibrillation, at an unspecified dose and frequency. At the time of the report, ATRIAL FIBRILLATION (Atrial fibrillation), DIZZINESS (feeling lightheaded), VERTIGO (sever vertigo.), ALOPECIA (alopecia spot/hair fell out), PAIN IN EXTREMITY (pain in arm went through arm to neck), NECK PAIN (burst of pain to neck), FACIAL PAIN (pain left side of face), PAIN (hurts when puts out laterally), HYPOAESTHESIA (numbness left side of face), BLOOD PRESSURE DECREASED (blood pressure dropped), MYALGIA (stomach(muscle) pains), ASTHENIA (weakness in the left arm), HEADACHE (headache) and MYALGIA (to whole left side of body being in pain) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Cardiac stress test: normal (normal) normal. On an unknown date, Computerised tomogram: normal (normal) normal. On an unknown date, Electrocardiogram: normal (normal) normal.     The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) was unknown.       Patient was advised not to receive the second dose because of all the symptoms had after getting the first dose of vaccination.  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, underlying medical history of hypertension and use of concomitant medication carvedilol are confounder.; Sender's Comments: 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, underlying medical history of hypertension and use of concomitant medication carvedilol are confounder.