discovered she was in heart failure; diagnosed with Acute Systolic Heart Failure; soreness at injection site; This spontaneous case was reported by a patient and describes the occurrence of CARDIAC FAILURE (discovered she was in heart failure) and ACUTE LEFT VENTRICULAR FAILURE (diagnosed with Acute Systolic Heart Failure) in an 84-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 006B21A and 032B21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Osteoporosis and Autoimmune disorder NOS (Autoimmune problems). Concomitant products included PARACETAMOL (TYLENOL), VITAMINS NOS and MINERALS NOS (MINERALS) for an unknown indication.   On 18-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 15-Apr-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. In July 2021, the patient experienced CARDIAC FAILURE (discovered she was in heart failure) (seriousness criteria hospitalization and medically significant) and ACUTE LEFT VENTRICULAR FAILURE (diagnosed with Acute Systolic Heart Failure) (seriousness criteria hospitalization and medically significant). On an unknown date, the patient experienced VACCINATION SITE PAIN (soreness at injection site). The patient was hospitalized from 21-Jul-2021 to 30-Jul-2021 due to ACUTE LEFT VENTRICULAR FAILURE and CARDIAC FAILURE. At the time of the report, CARDIAC FAILURE (discovered she was in heart failure), ACUTE LEFT VENTRICULAR FAILURE (diagnosed with Acute Systolic Heart Failure) and VACCINATION SITE PAIN (soreness at injection site) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In July 2021, Ejection fraction: unknown (Low) Low.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   No treatment medications provided by the reporter.   Patient reported she just had soreness at the injection site. Patient also stated that past July she had a health care problem and landed in the ICU. It was discovered she was in heart failure. Agent asked patient if she was diagnosed with Myocarditis/Pericarditis, and patient stated no. Patient stated that she was diagnosed with Acute Systolic Heart Failure. Patient stated that she never had this problem before. Patient said her Ejection Faction is low. Patient stated again that she never had a heart problem. Patient said that she would have been dead if not taken to ER. She stayed 10 days in hospital ICU, first in the ER, then taken to the ICU. Patient was in the hospital for 21July2021 and discharged on 30July 2021.  Company comment: This case concerns a 84 year old female with history of osteoporosis and autoimmune disorder who experienced serious unexpected events of cardiac failure and acute ventricular failure approximately two and half months after the second dose of Moderna Covid 19 vaccine.  Medical history of autoimmune disorder is a confounder. Rechallenge was not applicable. The benefit-risk relationship is not affected by this report.; Sender's Comments: This case concerns a 84 year old female with history of osteoporosis and autoimmune disorder who experienced serious unexpected events of cardiac failure and acute ventricular failure approximately two and half months after the second dose of Moderna Covid 19 vaccine.  Medical history of autoimmune disorder is a confounder. Rechallenge was not applicable. The benefit-risk relationship is not affected by this report.