New onset atrial fibrillation; Myocarditis/inflammation of the heart; pericardial effusion/he had a significant amount of inflammation and fluid around the heart; pericarditis; Tightness of chest; He went in for difficulty breathing; very tired; chest pain; This is a spontaneous report from a contactable consumer (patient's wife) from a Pfizer sponsored program. A 42-years-old male patient received bnt162b2 (PFIZER-BIONTECH COVID-19 VACCINE), dose 2 via an unspecified route of administration at age of 42 years on an unspecified date (Batch/Lot number was not reported) at 14:00 as single dose for covid-19 immunisation. Medical history was none. No family medical history relevant to AEs. There were no concomitant medications. The patient experienced new onset atrial fibrillation (AFib) since 27Apr2021 and hospitalized form 29Apr2021, myocarditis/ Inflammation of heart (2021), pericarditis (2021), and pericardial effusion (2021) after receiving second dose of the Pfizer BioNTech Covid-19 Vaccine. Patient sought medical treatment and was hospitalized twice, the first time being 29Apr2021. The patient was still dealing with issues and went into hospital 27Apr2021 (as reported). Since then, he has been going back and forth to hospital and was admitted twice for the same issues. He was diagnosed with Afib and inflammation of the heart. Reporter just wanted to know who needs to talk to because it seemed to be vaccine related. Patient has had to take time off of work and reporter has had to take time off work to take care of him. Patient stayed a week for the first AFib hospitalization. He got out of the hospital (2021) and was at home for a week. That Friday, he went back and was hospitalized for another week (2021). That admission was for both AFib and inflammation of the heart. They saw the inflammation the first time, but it was not a lot and said it was probably normal because of the AFib. When he went back for follow up, he had a significant amount of inflammation and fluid around the heart (2021). He was still dealing with it.  He had another issue with going to ER and this was Friday before last. He went in for difficulty breathing (2021) and was told he had more fluid around the heart. He was not admitted for that one. They gave him more medication to control the fluid. Reporter later stated it was prednisone and she did not have a dose, lot or expiration. She then said the dose was increased after he went for follow up and had more fluid.  The first time patient was taken to the emergency they could not find anything and the next day, she (reporter) called 911 from her home and saw that he was experiencing some cardiac issues and saw that he was admitted and told he had AFIB. When she called 911 from her home, they transported by ambulance to (#) Hospital in (#), (#) and that was when he admitted and diagnosed with AFIB. Since # was out of their network, he was transferred to # that same evening or day to # and he was there about a week. Then he was released after a week and still had a hard time breathing and walking a few steps with trying to catch his breath and had chest pain and was very tired (2021). Then he went to a follow up that Friday after being released. Unknown doctor in (#) and then he was readmitted at the follow up appointment to #. He was in the hospital for a week that time as well. He was discharged and they prescribed him medication and then he came back home on medication and he has been on several medications. The one to reduce inflammation, starts with a P and she cannot remember name. He finished it and went to a follow up. After he finished medication, he was experiencing side effects (2021) such as chest pain, difficulty breathing and tightness of chest. She then remembered it was Prednisone that he was on, unknown dose, and it is in pharmacy vial with no lot or expiration. There was no seal, and count size is unknown. He no longer has any left. He went to the ER in (#) because he was experiencing the same symptoms. They saw more fluid collecting and put him on the same medication but a higher dosage of Prednisone. This dose is 10mg, 4 tablets by mouth daily.  It was also in a pharmacy vial with no lot or expiration. This was where he was now. He has been out of work and so has reporter. The patient had MRI, XRays, Echo, Blood Test and was still doing blood test (in 2021). He has to go back this week. Everything came back as unknown for what caused this. The outcome of events myocarditis/ Inflammation of heart and AFib was recovered/resolved with sequel in 2021, of other events was unknown.  Information on the lot/ batch number has been requested.