Atrial fibrillation; his heart rate on the pulse ox it was 180; This is a spontaneous report from a contactable consumer (Patient's wife). A 73-year-old male patient (husband) received 1st dose of BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE, Solution for injection, Batch/Lot Number: EM9810), intramuscularly administered in arm left on 06Feb2021 at age of 73 years old at single dose for covid-19 immunisation. Medical history included atrial flutter, cardiac ablation from Jan2020, tooth infection, root canal, ongoing prostate issues. Concomitant medication included tamsulosin hydrochloride (FLOMAX) taken for prostate issues from an unspecified start date and ongoing, medication for nasal congestion (He had a lot of sinus issues. It was mainly nasal sprays that he used). The patient previously took penicillin BK for tooth infection, clindamycin for tooth infection, amoxicillin for tooth infection, paracetamol (TYLENOL) for pain. The patient experienced atrial fibrillation on 16Feb2021. This case was a serious report with Seriousness criteria-Caused/prolonged hospitalization. Reporter said that her husband got the first dose of the vaccine on 06Feb2021 and on 15Feb2021 he went to the cardiologist. She said that he had a history of atrial flutter and had an ablation over a year ago in Jan2020. She said that he went in for a routine check. She said that he had been off of his cardiac medications because he was doing fine after the ablation. The doctor told him to follow up in a year. On 16Feb2021, he started having weird things going on with his heart. He took some medication to help the rate of his heart. Reporter clarified that he took Metoprolol (TOPROL XL) 50mg that he had in the house. The doctor told him to take it in case something happened. She said that there was the chance that he had Afib and was just asymptomatic. They never saw any evidence of Afib previously though, just AFlutter. He had no episodes of Afib. She said that previously he went off of his medications and was doing ok. They were told to buy a watch that monitors his heart rate. Reporter said that when she checked his heart rate on the pulse ox it was 180. She called an ambulance and he was admitted to the hospital for atrial fibrillation. She said that they had to do a cardioversion in the ambulance on the way there and it was a significant occurrence. Her husband experienced Afib about 10 days later after the vaccine, was cardioverted on the way to the hospital and was hospitalized due to atrial flutter. Reporter stated doctor told them they didn't see any correlation with the vaccine. Reporter wanted to know if these symptoms were reported before. She said that during this period of time, he had been on 3 different antibiotics for a tooth infection and had a root canal. She said that he took these from the beginning of Jan2021 for about a week each. She said that his tooth infection was not any better or was worse and they would try another antibiotic. Reporter clarified that the antibiotics were Penicillin BK first, then he was on Clindamycin the second time, then was on Amoxicillin the 3rd time. He was also on Tylenol 3 for the pain during this as well.  The patient took 2nd dose of BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE, Lot number: EM6198) intramuscularly in the Left arm on 01Mar2021 at single dose for covid-19 immunisation. The outcome of events was unknown.