Heart Failure With Severely Reduced Ejection Fraction Following Covid-19 vaccine; This is a literature report.  A 43-year-old male patient received BNT162b2 (BNT162B2), 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, single), for COVID-19 immunisation. The following information was reported: CARDIAC FAILURE (medically significant) with onset 2021, 1 week 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: 1841, notes: units: unknown; Catheterisation cardiac: no disease; Echocardiogram: unknown; Ejection fraction: 22 %, notes: Stage 3 diastolic dysfunction; 62 %, notes: 4 months later; Right ventricular systolic pressure: 50-55 mmHg; Troponin: 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 43 year old male. Symptom onset was 1 week after the second dose of Pfizer. Patients 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. Guidedline -directed medical therapy given to the patient was Carvedilol. 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 insome.  No follow-up attempts are possible; information about lot/batch number cannot be obtained. No further information is expected; Sender's Comments: Based on the current available limited information in the case provided, the causal association between the events Cardiac failure and the use of suspect product BNT 162B2 cannot be fully excluded. The impact of this report on the benefit-risk profile of the Pfizer product and on the conduct of the study 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-202300165611 Same article/drug/event and different patient;US-PFIZER INC-202300165612 Same article/drug/event and different patient;US-PFIZER INC-202300165613 Same article/drug/event and different patient;