imaging revealed left ventricular systolic failure/left ventricle which is supposed to be ejecting 60% is only ejecting 40%; This spontaneous case was reported by a consumer and describes the occurrence of LEFT VENTRICULAR FAILURE (imaging revealed left ventricular systolic failure/left ventricle which is supposed to be ejecting 60% is only ejecting 40%) in a 44-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 005C21A and 005C21A) for COVID-19 vaccination.     No Medical History information was reported.   On 06-May-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 04-Jun-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 18-Nov-2021,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced LEFT VENTRICULAR FAILURE (imaging revealed left ventricular systolic failure/left ventricle which is supposed to be ejecting 60% is only ejecting 40%) (seriousness criterion medically significant). The patient was treated with CHLORTHALIDONE for Blood pressure high, at an unspecified dose and frequency and ALBUTEROL [SALBUTAMOL] for Breathing difficult, at an unspecified dose and frequency. At the time of the report, LEFT VENTRICULAR FAILURE (imaging revealed left ventricular systolic failure/left ventricle which is supposed to be ejecting 60% is only ejecting 40%) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 27-Oct-2021, Blood test: normal (normal) everything was normal. On 27-Oct-2021, Carbon dioxide: abnormal (abnormal) Carbon dioxide was 34mm OL/L. On 12-Nov-2021, Cardiac stress test: positive (Positive) Positive. On 18-Nov-2021, Cardiac stress test: positive (Positive) Positive. On 18-Nov-2021, Echocardiogram: normal (normal) echo was fine. On 18-Nov-2021, Electrocardiogram: abnormal (abnormal) The imaging revealed left ventricular systolic failure which they believed came from cardiomyopathy. Left ventricle which was supposed to be ejecting 60% was only ejecting 40%. On an unknown date, Blood pressure measurement: high (High) top number was high, monitored BP for 2 weeks and was found to be consistently high. On an unknown date, Ejection fraction: abnormal (abnormal) supposed to be ejecting 60% was only ejecting 40% which was pretty bad.. On an unknown date, Electrocardiogram: abnormal (abnormal) Abnormal.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   Concomitant product use was not provided by the reporter. About a month after the patient got the 2nd dose (beginning of Jul2021) had a hard time breathing so consulted the healthcare provider (HCP). They took blood pressure (BP) and the "top number" was high. They monitored BP for 2 weeks and this was found to be consistently high. Patient was started on a medication but this did not give any relief so was shifted to another medication. Again, this did not give the relief of the condition. Patient was eventually given Chlorthalidone. The imaging revealed left ventricular systolic failure which was believed to be came from cardiomyopathy. The left ventricle which was supposed to be ejecting 60% was only ejecting 40% and her doctor mentioned that this could be due to the vaccine. Patient had not experienced symptoms like this before receiving the Moderna COVID-19 and patient was extremely physically active.  The patient received 2 unspecified medications. Company comment- This case concerns a 44-year-old, female patient with no relevant medical history reported, who experienced the unexpected event of left ventricular failure. The event occurred 5 months and 14 days after the second dose of mRNA-1273. The rechallenge was not applicable since the event happened after the second dose. The benefit-risk relationship of mRNA-1273 is not affected by this report. information was requested.; Sender's Comments: This case concerns a 44-year-old, female patient with no relevant medical history reported, who experienced the unexpected event of left ventricular failure. The event occurred 5 months and 14 days after the second dose of mRNA-1273. The rechallenge was not applicable since the event happened after the second dose. The benefit-risk relationship of mRNA-1273 is not affected by this report. information was requested.