Heart Failure With Severely Reduced Ejection Fraction Following Covid-19; This is a literature report.  A 22-year-old male patient received BNT162b2 (Pfizer-BioNTech COVID-19 Vaccine), in 2021 as dose 2, single (Batch/Lot number: unknown) for covid-19 immunisation. The patient's relevant medical history and concomitant medications were not reported. Vaccination history included: Bnt162b2 (DOSE 1), for COVID-19 immunization. The following information was reported: CARDIAC FAILURE (medically significant), 2 weeks after the suspect product(s) administration, outcome "unknown", described as "Heart Failure With Severely Reduced Ejection Fraction Following Covid-19". The patient underwent the following laboratory tests and procedures: Brain natriuretic peptide: 2187, notes: units: unknown; Catheterisation cardiac: no disease; mild Pulmonary hypertension; Echocardiogram: moderately to severely dilated left, notes: ventricular 15; 20-25 %, notes: in one month; Ejection fraction: Reduced; Magnetic resonance imaging heart: dilated left ventricle, notes: no gadolinium enhancement; Red blood cell sedimentation rate: 10, notes: units: unknown; Troponin: less than 0.03, notes: units: unknown. Therapeutic measures were taken as a result of cardiac failure.  With the rise of the pandemic, the development of the COVID-19 vaccine has helped alleviate the burden on the healthcare system. However, rare cardiac side effects have been reported, especially within the young healthy population. Herein, authors present a case series of four patients who received the Pfizer mRNA COVID-19 vaccine and were noted to have heart failure with severely reduced ejection fraction (<= 25%) a few weeks following the 2 dose of the Pfizer vaccine. Patient is a 22-year-old male. Symptom onset was 2 weeks after the second dose of Pfizer. Patient had no prior known cardiac history or predisposing conditions. All patients commonly reported clinical symptoms of heart failure including fatigue, orthopnea, paroxysmal nocturnal dyspnea, and peripheral edema starting within three weeks from receiving the second dose of the Pfizer COVID-19 Vaccine. Guideline -directed medical therapy given to the patient was lisinopril, metoprolol, sacubitril-valsartan, spirinolactone. Conclusion: The relationship between the novel mRNA COVID-19 vaccine and cardiomyopathy remains to be an area in need of further investigation. Despite the unclear mechanism, management remains to be with GDMT and advanced therapies as indicated. EF recovery and improved clinical outcomes can be achieved in some.  No follow up attempts are possible. No further information is expected.; Sender's Comments: Based on the information provided in the narrative, a causal association between the event Cardiac Failure and the suspect drug cannot be completely excluded. The impact of this report on the benefit/risk profile of the Pfizer product is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to Regulatory Authorities, Ethics Committees and Investigators, as appropriate.,Linked Report(s) : US-PFIZER INC-PV202300072743 Same article/drug/event and different patient;