Left ventricular thrombus; Chronic systolic heart failure; severe sepsis; Acute kidney injury; Hyponatraemia; Transient rash in lower extremities; hypotension; Dehydration; Diarrhoea; Nausea; Vomiting; Fever; This spontaneous case was reported by a consumer and describes the occurrence of CARDIAC VENTRICULAR THROMBOSIS (Left ventricular thrombus), CHRONIC LEFT VENTRICULAR FAILURE (Chronic systolic heart failure), SEPSIS (severe sepsis), ACUTE KIDNEY INJURY (Acute kidney injury), HYPONATRAEMIA (Hyponatraemia), RASH (Transient rash in lower extremities), HYPOTENSION (hypotension), DEHYDRATION (Dehydration), DIARRHOEA (Diarrhoea), NAUSEA (Nausea), VOMITING (Vomiting) and PYREXIA (Fever) in a 41-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination.     The patient's past medical history included Stent insertion NOS (stening earlier this month) and Cardiac catheterisation (Cardiac stents to mid proximal left anterior descending artery on the 1st septal perforator with 2.5 x 38 mm drug-eluting oynx stent and proximal left anterior descending artery using a 3.0 x 12 mm drug-eiuting synergy). Concurrent medical conditions included Coronary artery disease (ST elevation myocardial infarction involving left anterior descending (LAD) coronary artery, Pericarditis, Chronic systolic heart failure (with reduced ejection fraction), Hyperlipidemia, Tobacco user, Chest pain, Chronic back pain and Penicillin allergy (Allergy to amoxicillin - Rash, urticarial) since 19-May-2021. Concomitant products included GLYCERYL TRINITRATE (NITROSTAT) for Chest pain, HYDROCODONE BITARTRATE, PARACETAMOL (NORCO) for Chronic back pain, ACETYLSALICYLIC ACID (ECOTRIN), ATORVASTATIN CALCIUM (LIPITOR) and LISINOPRIL DIHYDRATE (PRINIVIL) for Heart attack, METOPROLOL SUCCINATE (TOPROL XL) for Heart failure, APIXABAN (ELIQUIS) for Thrombus, LIDOCAINE (LIDODERM), OMEPRAZOLE (PRILOSEC [OMEPRAZOLE]), PRASUGREL HYDROCHLORIDE (EFFIENT) and SPIRONOLACTONE (ALDACTONE [SPIRONOLACTONE]) for an unknown indication.    On 15-Jun-2021, the patient received dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 15-Jun-2021, the patient experienced DIARRHOEA (Diarrhoea) (seriousness criterion hospitalization), NAUSEA (Nausea) (seriousness criterion hospitalization), VOMITING (Vomiting) (seriousness criterion hospitalization) and PYREXIA (Fever) (seriousness criterion hospitalization). On an unknown date, the patient experienced CARDIAC VENTRICULAR THROMBOSIS (Left ventricular thrombus) (seriousness criteria hospitalization and medically significant), CHRONIC LEFT VENTRICULAR FAILURE (Chronic systolic heart failure) (seriousness criterion hospitalization), SEPSIS (severe sepsis) (seriousness criteria hospitalization and medically significant), ACUTE KIDNEY INJURY (Acute kidney injury) (seriousness criteria hospitalization and medically significant), HYPONATRAEMIA (Hyponatraemia) (seriousness criterion hospitalization), RASH (Transient rash in lower extremities) (seriousness criterion hospitalization), HYPOTENSION (hypotension) (seriousness criterion hospitalization) and DEHYDRATION (Dehydration) (seriousness criterion hospitalization). The patient was hospitalized on 21-Jun-2021 due to CARDIAC VENTRICULAR THROMBOSIS and CHRONIC LEFT VENTRICULAR FAILURE. The patient was treated with ALBUMIN HUMAN (intravenous) at a dose of 12.5 g twice a day; FUROSEMIDE (LASIX [FUROSEMIDE]) (intravenous) at a dose of 20 mg; LEVOFLOXACIN (LEVAQUIN) (oral) at a dose of 500 mg; MAGNESIUM SULFATE (intravenous) at a dose of 2 g in 50mL water for injection and MAGNESIUM SULFATE (intravenous) at a dose of 4 g in 100Ml sterile water. At the time of the report, CARDIAC VENTRICULAR THROMBOSIS (Left ventricular thrombus), CHRONIC LEFT VENTRICULAR FAILURE (Chronic systolic heart failure), SEPSIS (severe sepsis), ACUTE KIDNEY INJURY (Acute kidney injury), HYPONATRAEMIA (Hyponatraemia), HYPOTENSION (hypotension), DEHYDRATION (Dehydration), DIARRHOEA (Diarrhoea), NAUSEA (Nausea), VOMITING (Vomiting) and PYREXIA (Fever) outcome was unknown and RASH (Transient rash in lower extremities) had resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 23-Jun-2021, Blood pressure measurement: 98/60 (Low) Low. On 23-Jun-2021, Body temperature: 36.8 (normal) 36.8. On 23-Jun-2021, Heart rate: 96 (normal) Normal. On 23-Jun-2021, Oxygen saturation: 95 % (normal) Normal. On 23-Jun-2021, Respiratory rate: 18 (normal) 18. On an unknown date, Alanine aminotransferase: 109 (normal) Normal. On an unknown date, Anion gap: 18.0 (normal) Normal. On an unknown date, Bilirubin urine: 1+ (normal) Normal. On an unknown date, Blood albumin: 2.5 (normal) Normal. On an unknown date, Blood alkaline phosphatase: high (High) High. On an unknown date, Blood bicarbonate: 19.6 (normal) Normal. On an unknown date, Blood bilirubin: 2.5 (normal) Normal. On an unknown date, Blood chloride: 93 (normal) Normal. On an unknown date, Blood creatinine: 3.18 (normal) Normal. On an unknown date, Blood glucose: 134 (normal) Normal. On an unknown date, Blood lactic acid: high (High) High. On an unknown date, Blood potassium: 3.4 (normal) Normal. On an unknown date, Blood pressure measurement: 93/45 (Low) 93/45. On an unknown date, Blood sodium: 128 (normal) Normal. On an unknown date, Blood urea: 51 (normal) Normal. On an unknown date, Body temperature: 37.9 (normal) 37.9. On an unknown date, Calcium ionised: 0.97 (normal) 0.97. On an unknown date, Chest X-ray: no abnormality detected (normal) Normal. On an unknown date, Eosinophil count: 0.7 (normal) Normal. On an unknown date, Glomerular filtration rate: 23- 27 (normal) other - 23 - 27. On an unknown date, Haematocrit: 35.5 (normal) Normal. On an unknown date, Haemoglobin: 12.8 (normal) Normal. On an unknown date, Heart rate: 99 (normal) 99. On an unknown date, International normalised ratio: 1.9 (normal) Normal. On an unknown date, Liver function test: high (High) High. On an unknown date, Neutrophil count: 13.3 (normal) Normal. On an unknown date, Oxygen saturation: 96 % (normal) Normal. On an unknown date, Protein urine: 2+ (normal) Normal. On an unknown date, Prothrombin time: 21.1 (normal) Normal. On an unknown date, Red blood cell count: 4.08 (normal) Normal. On an unknown date, Respiratory rate: 19 (normal) 19. On an unknown date, Urobilinogen urine: 4 (normal) Normal. On an unknown date, White blood cell count: 15.8 (normal) Normal.     The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown) was unknown.   For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   Company Comment:  This case concerns a 41-year-old, male patient with no previous relevant medical history, who experienced the unexpected events of cardiac ventricular thrombosis, chronic left ventricular failure, sepsis, acute kidney injury, hyponatremeia, rash, hypotension, dehydration, diarrhea, nausea, vomiting, and pyrexia. Nausea, vomiting, diarrhea and pyrexia occurred on the same day after the first dose of mRNA-1273 (Moderna COVID-19 Vaccine). Chronic left ventricular failure remains as a confounder. The rechallenge was not applicable since only information about the first dose was disclosed. The reporter assessed the events as possible. The benefit-risk relationship of mRNA-1273 (Moderna COVID-19 Vaccine) is not affected by this report.   Most recent FOLLOW-UP information incorporated above includes: On 23-Sep-2021: Follow-Up received. Past medical history, laboratory test, Concomitant medication and treatment medications are updated.; Sender's Comments: This case concerns a 41-year-old, male patient with no previous relevant medical history, who experienced the unexpected events of cardiac ventricular thrombosis, chronic left ventricular failure, sepsis, acute kidney injury, hyponatremeia, rash, hypotension, dehydration, diarrhea, nausea, vomiting, and pyrexia. Nausea, vomiting, diarrhea and pyrexia occurred on the same day after the first dose of mRNA-1273 (Moderna COVID-19 Vaccine). Chronic left ventricular failure remains as a confounder. The rechallenge was not applicable since only information about the first dose was disclosed. The reporter assessed the events as possible. The benefit-risk relationship of mRNA-1273 (Moderna COVID-19 Vaccine) is not affected by this report.