Acute decompensated heart failure; eosinophilic injury-mediated myocarditis; Acute left arm pain; This literature-non-study case was reported in a literature article and describes the occurrence of CARDIAC FAILURE ACUTE (Acute decompensated heart failure), EOSINOPHILIC MYOCARDITIS (eosinophilic injury-mediated myocarditis) and PAIN IN EXTREMITY (Acute left arm pain) in a 53-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination.   LITERATURE REFERENCE: Myocarditis following COVID-19 mRNA vaccination. Proc (Med Cent). 2021;35(2):209     No Medical History information was reported.    On an unknown date, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced CARDIAC FAILURE ACUTE (Acute decompensated heart failure) (seriousness criteria hospitalization and medically significant), EOSINOPHILIC MYOCARDITIS (eosinophilic injury-mediated myocarditis) (seriousness criteria hospitalization and medically significant) and PAIN IN EXTREMITY (Acute left arm pain) (seriousness criterion hospitalization). At the time of the report, CARDIAC FAILURE ACUTE (Acute decompensated heart failure), EOSINOPHILIC MYOCARDITIS (eosinophilic injury-mediated myocarditis) and PAIN IN EXTREMITY (Acute left arm pain) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Biopsy heart: eosinophilic injury-mediated (abnormal) eosinophilic injury-mediated myocarditis.     The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown) was unknown.   For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter considered CARDIAC FAILURE ACUTE (Acute decompensated heart failure), EOSINOPHILIC MYOCARDITIS (eosinophilic injury-mediated myocarditis) and PAIN IN EXTREMITY (Acute left arm pain) to be related.    No concomitant and treatment medication were provided by reporter.  Company Comment:  This is a literature non-study case concerning a 53-year-old female patient with no medical history reported, who experienced the unexpected serious (hospitalization, medically significant) adverse event of special interest of Cardiac failure acute (reported as Acute decompensated heart failure), expected serious (hospitalization, medically significant) adverse event of special interest of Eosinophilic myocarditis (reported as Eosinophilic injury-mediated myocarditis) and unexpected serious (hospitalization) event of Pain in extremity (reported as Acute left arm pain), after receiving the first dose of mRNA-1273 vaccine. Initially, patient experienced acute left arm pain 3 days after the first dose of the mRNA-1273 vaccine and later found to have Acute decompensated heart failure and Eosinophilic injury-mediated myocarditis confirmed by endomyocardial biopsy, unknown days post-vaccination. Date of vaccination and onset of events were not specified. Treatment details were not provided in the case. At the time of reporting, the outcome of the events were unknown. The benefit-risk relationship of mRNA-1273 is not affected by this report.   This case was linked to MOD-2022-513579, MOD-2022-513580, MOD-2022-513533 (Patient Link).; Sender's Comments: This is a literature non-study case concerning a 53-year-old female patient with no medical history reported, who experienced the unexpected serious (hospitalization, medically significant) adverse event of special interest of Cardiac failure acute (reported as Acute decompensated heart failure), expected serious (hospitalization, medically significant) adverse event of special interest of Eosinophilic myocarditis (reported as Eosinophilic injury-mediated myocarditis) and unexpected serious (hospitalization) event of Pain in extremity (reported as Acute left arm pain), after receiving the first dose of mRNA-1273 vaccine. Initially, patient experienced acute left arm pain 3 days after the first dose of the mRNA-1273 vaccine and later found to have Acute decompensated heart failure and Eosinophilic injury-mediated myocarditis confirmed by endomyocardial biopsy, unknown days post-vaccination. Date of vaccination and onset of events were not specified. Treatment details were not provided in the case. At the time of reporting, the outcome of the events were unknown. The benefit-risk relationship of mRNA-1273 is not affected by this report.