has possible atrial fibrillation; Arm would get hurt; her arm felt like a bruise; irregular heart rates; She'll have  a slight cough and she feels a little short of breath then she's fine. That happened leaving the Covid 19 vaccine site. And it's been happening more at night.; When probing for specific event information she reports it's kind of like she coughs a little more and she is a little more short of breath and it's happening more often; This is a spontaneous report from a contactable consumer (patient).  A 63-year-old female patient received the first dose of bnt162b2 (PFIZER-BIONTECH COVID-19 VACCINE), at the age of 63 years, via an unspecified route of administration on 27Mar2021 04:06 (Batch/Lot number was not reported) as a single dose for covid-19 immunization. The patient's medical history included asthma, hysterectomy, dark chocolate or red dye (she starts coughing and has an allergic reaction and shortness of breath), bursitis (in her right). The patient's concomitant medications were not reported. The patient previously took penicillin, experienced allergy and had really ad hives (several years ago) she was given a cream to put on. She had to get another medication and she doesn't remember the name. That medication made her dizzy and she couldn't even get out of bed so they had to half the dosage. When she had her hysterectomy she learned she couldn't take any types of "cillins" medications. The patient had been watching her heart rate with a device and since getting the Covid 19 vaccine she's noticed her heartrate was always higher than it normally is. Her heartrate was going crazy, the device was not recording right. She reports that for the last 2 days the device has been telling her she has possible atrial fibrillation. This is worrying her. She doesn't feel anything different. She was usually hyper. Her resting heartrate was higher. Normally her resting heartrate was in the 80s (beats per minute) Now it's going up to the 90s (beats per minute) then her heartrate drops to 40 something (beats per minute) Then the device said her heartrate was 118 and 107 and she's not even doing anything. She hasn't even worked out yet. She doesn't like to take medicine. Medications don't work out with her. She had a slight cough and she feels a little short of breath then she's fine. That happened leaving the Covid 19 vaccine site. And it's been happening more at night. It was reported that she feels fine. She has no other symptoms. She's been reporting online. Clarified she's reporting online through the V check through the CDC. She's been trying to get the Covid 19 vaccine forever. She did research on all the Covid vaccines and she felt more confident with the Pfizer Covid 19 vaccine. Her daughter was against the Covid 19 vaccine. Her daughter thinks the vaccine was just going to kill her. She reports she was healthy and she works out 6 days a week.  She recently tried to get a CT scan for her heart. Her husband's cardiologist recommended her husband have a CT scan of his heart and she decided she needed a CT scan too. She's also watching her heartrate on her watch. Her husband's heartrate is completely normal and stable on the device so she knows the device isn't messed up. It was also reported that the device will tell her she has too much muscle movement and she's standing completely still. Then she'll get the device to record her heart rhythm and it goes sporadic. The device tells her 90 beats per minute at resting then over 100 beats per minute. Her heartrate on the device was going up and down a lot. When she's been watching the device record her heart, it looks like it's going crazy. Her heartrate goes way up and way down like in the 40s (beats per minute) She noticed when her heartrate is in the 40s (beats per minute) and she's never had her heartrate go down that far, it's really really weird. She thinks maybe she'll get back to normal. She keeps watching hear heartrate. She reports she noticed her heartrate right away on Saturday evening after she received the Covid 19  vaccine. Her heartrate was higher than normal for resting, it was in the 90s (beats per minute). Her resting heartrate is usually in the 60-80s (beats per minute) and it was the in 90s. Now the device says possible atrial fibrillation. It was further reported that she received the Covid 19 vaccine in her left arm because she has bursitis in her right. If she hit her arm the second day after the Covid 19 vaccine, her arm would hurt. Her arm felt better the next day. She clarifies, on Sunday, 28Mar2021, she noticed her arm felt like a bruise and that was it. Then the next day on Monday, 29Mar2021, the feeling was gone. She didn't have any redness. The outcome of the events her arm felt like a bruise and arm would get hurt was recovered on 29Mar2021, irregular heart rates, dyspnea, cough was not recovered and unknown outcome for has possible atrial fibrillation.  Information on the lot/batch number has been requested.