arrhythmia; tachycardia; arm was slightly swollen; arm was slightly swollen and very very tender and sore; arm was slightly swollen and very very tender; This is a spontaneous report from a contactable consumer (patient). This 74-year-old female patient received the 2nd dose of bnt162b2 (PFIZER-BIONTECH COVID-19 VACCINE, lot number: 301308A) via an unspecified route of administration in the left arm on 17Sep2021 at about 10-10:30am at 74 years old as single dose for COVID-19 immunization. Medical history included 6 kidney stones, TB as a young child before age 5, pancreatic cancer about 15 years ago with surgery and chemo and she was alive and doing well. She had a PET scan Tuesday and there was no recurrence. Concomitant medications were unknown. The patent previously received the 1st dose of bnt162b2 (PFIZER-BIONTECH COVID-19 VACCINE, lot number: FD8448) via an unspecified route of administration in the left arm on 27Aug2021 about 9:15-9:30 am at age of 74 years old as single dose for COVID-19 immunization, experiencing a little achiness the evening of her 1st dose and soreness the next day. The patient stated she hadn't had a vaccine since she was in her late 20's, she had a few injections before she went on vacation but no vaccine since her late 20's. She believed with rubella she had 3 weeks of joint pain and fever. The patient stated she had had an adverse reaction to every vaccine she had ever had and she didn't do the flu, shingle or pneumonia shot as she had always had very bad adverse events. The patient declined to report as they were not necessarily Pfizer and was long ago. Stated Polio also. The patient was calling to report a suspected side effect on the Pfizer Covid vaccination for herself. The patient experienced arrhythmia or tachycardia on 29Sep2021 that started 12 days after the second vaccine and she had at least one episode daily for 6 days. The patient stated it seemed to have subsided now. The patient relayed that within the past 2 years she had a few instances of atrioventricular nodal reentrant tachycardia (AVNRT). The patient provided that her instances were few and far between and she could stop them herself until recently. The patient stated that she had Verapamil in case she can't stop them on her own. The patient relayed she had to take 1 for the 1st time in 2 years. The patient relayed she did see a cardiologist this past Tuesday 12Oct2021 and they did an EKG and he agreed it was probably a side effect of the vaccine because she had a history of this before. The patient stated he told her everything was fine with the EKG. The patient stated that from 29Sep2021 through 05Oct2021 it happened at least one a day and on 30Sep2021 she had to take Verapamil to get the rapid heart beat stopped. It took a while to get the referral and appointment for the cardiologist who was also an electrophysiologist that specialized in arrhythmias. The patient stated with the 2nd one her arm was slightly swollen and very very tender and sore for 10 days to 2 weeks and that gradually subsided each day, it was very very sore to touch. The patient stated the arrhythmia started on the 12th day (on 29Sep2021). The patient stated she waited a long time and researched because she had had an adverse reaction to every vaccine she had ever had and she didn't do the flu, shingle or pneumonia shot as she had always had very bad adverse events. Her provide said because of the newer technology with MrNA he suspected she would be fine and she waited a long time and did a lot of research and decided Pfizer was the best one for her. The patient stated she didn't want to survive cancer to die of Covid and she was more afraid of the vaccine than Covid then the variant happened and it made her nervous so she did it and her family wanted her to have it. The patient stated she believed arrhythmia was a possible side effect from what she has read, that according to our information it was. She was concerned about myocarditis and pericarditis and those can happen with Moderna and Guillen Barre with the Johnson & Johnson so she picked Pfizer as it had fewer side effects she was concerned about. The patient had EKG and had a PET scan that morning of 12Oct2021 and she saw the doctor late in the afternoon but didn't think the contrast would have any effect of anything. The patient stated he told her everything was fine with the EKG. AE(s) require a visit to Physician Office. The patient stated these were certainly not life threatening but she always reported side effects from when she changed medication if it's serious. Stated she wanted them to know her experience was not severe and didn't require intervention but she did read it was a possible side effect and wanted to help the statistics that that happened. Outcome of the events tachycardia and arrhythmia was recovered on 05Oct2021, of the event arm was slightly swollen was recovering,  of the other events was unknown.   Follow-up attempts are completed. No further information is expected.