Fibrillation; falling asleep most of the time; she started feeling so tired / no energy; This spontaneous case was reported by a patient and describes the occurrence of CARDIAC FIBRILLATION (Fibrillation) in a 77-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 017F21A, 023M20A and 004M20A) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Blood pressure abnormal (Patient did not consider it was a high BP which was registered as 150s). Concomitant products included SOTALOL for Blood pressure abnormal.   On 26-Jan-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 23-Feb-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 09-Nov-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 01-Jan-2022, the patient experienced HYPERSOMNIA (falling asleep most of the time) and FATIGUE (she started feeling so tired / no energy). In August 2022, the patient experienced CARDIAC FIBRILLATION (Fibrillation) (seriousness criterion medically significant). At the time of the report, CARDIAC FIBRILLATION (Fibrillation), HYPERSOMNIA (falling asleep most of the time) and FATIGUE (she started feeling so tired / no energy) was resolving.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In August 2022, Echocardiogram: Patient  had a problem with fibrillation. In August 2022, Electrocardiogram: Patient  had a problem with fibrillation. On an unknown date, Blood pressure measurement: Blood pressure was registered as 150s.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   Patient received first booster on 09-Nov-2021. Patient started feeling so tired, with no energy and was falling asleep most of the time. Patient was visited with regular doctor in Apr-2022 and was seen by doctor assistant in Aug-2022.Patient no longer felt that tired anymore and patient now able to do something. Patient did not have any previous history of myocarditis. Treatment information was not provided.  Company comment-This spontaneous case concerns an elderly female patient aged 77 years with relevant medical history of Blood pressure abnormal (BPs registering as 150s) reported, who experienced the unexpected, serious (medically significant) AESI event of Cardiac fibrillation and non-serious unexpected, AESI event of Hypersomnia. The event Cardiac fibrillation occurred about 9 months after, Hypersomnia about two months after third (booster) dose of mRNA-1273 vaccination. Patient had received initial two doses of same vaccine at an interval of 28 days. Patient started feeling so tired, with no energy and was falling asleep most of the time about 2 months after 3rd dose. Consulted her doctor 4 months later, EKC and echocardiogram was done and was told that she had a problem with fibrillation. Her blood pressure medication was changed to Sotalol. Currently, her symptoms have improved. She was told that she had "fibrillation problem" in Aug2022. No further information on risk factors, clinical course, investigations reports was available for review. Outcome of the events was resolving at the time of report. Elderly age a risk factor and relevant medical history remains as confounder to the event Cardiac fibrillation. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.; Sender's Comments: This spontaneous case concerns an elderly female patient aged 77 years with relevant medical history of Blood pressure abnormal (BPs registering as 150s) reported, who experienced the unexpected, serious (medically significant) AESI event of Cardiac fibrillation and non-serious unexpected, AESI event of Hypersomnia. The event Cardiac fibrillation occurred about 9 months after, Hypersomnia about two months after third (booster) dose of mRNA-1273 vaccination. Patient had received initial two doses of same vaccine at an interval of 28 days. Patient started feeling so tired, with no energy and was falling asleep most of the time about 2 months after 3rd dose. Consulted her doctor 4 months later, EKC and echocardiogram was done and was told that she had a problem with fibrillation. Her blood pressure medication was changed to Sotalol. Currently, her symptoms have improved. She was told that she had "fibrillation problem" in Aug2022. No further information on risk factors, clinical course, investigations reports was available for review. Outcome of the events was resolving at the time of report. Elderly age a risk factor and relevant medical history remains as confounder to the event Cardiac fibrillation. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.