elevated heart rate; Heart rate high; sweats at night; This is a spontaneous report from a contactable Nurse reported for herself. A 76-year-old female patient received second dose of bnt162b2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE Solution for injection Batch/Lot number was not reported) via an unspecified route of administration on 20Feb2021 (at the age of 76-years-old) as single dose for COVID-19 immunisation. Medical history included palpitations from an unknown date and unknown if ongoing. Concomitant medications were not reported. Historical vaccine included first dose of bnt162b2 on 20Jan2021 for COVID-19 immunisation. Patient queried asking if her elevated heart rate was a side effect from the vaccine and how long it was expected to last and had anyone died from the vaccine and have you received any calls from people who had experienced this. It was reported that she had both doses of the Pfizer vaccine, her second dose of the vaccine was on 20Feb and on 23Feb she went to the ER and was admitted for 5 hours. On 23Feb2021, she had been experiencing an elevated heart rate around 120bpm, heart rate high, sweats at night. She had spoken to her doctor and was advised to increase her dose of metoprolol. She wants to file a report, she was a registered nurse, retired. The caller had the Pfizer COVID vaccine, she had the first dose 20Jan2021, then she did not have any problems. The caller believed that the second dose was more potent, and on 20Feb, 3 days after she received the vaccine, she noticed her heart rate was going up to around 150. The problem was she did not have any symptoms. The caller took her vital signs while watching TV, her husband is a doctor. The caller had no symptoms then she had sweats at night and couldn't take it anymore, so she went to the Emergency Room. The caller was worked up and they did all the tests, which came back negative. The Emergency Room did an EKG two times, they drew troponins two times, they hydrated her with Lactated Ringers solutions, she consumed about 1,500 ccs, pulse was high, it came down to 120, not real down. Then the Emergency Room decided to let her go, she stayed there for 5 hours. The caller called her primary doctor. The caller already takes metoprolol for blood pressure and sometimes she would also have tachycardia would have palpitations so she would have to take extra then. The caller always takes it for her blood pressure and she always had symptoms if her heart rate was high and has to add more metoprolol then. She was still monitoring her heart rate, her primary care provider gave her something to go by if the heart rate goes up to 120, she was to take another 50mg, she could adjust it. Description of complaint: The caller already took metoprolol for blood pressure and sometimes she would also have tachycardia would have palpitations so she would have to take extra then, always takes it for her blood pressure and she always had symptoms if her heart rate was high and had to add more metoprolol then. Product strength and count size dispensed: metoprolol. Caller declined safety report, no additional information or details captured at this time. The patient underwent lab tests and procedures which included EKG resulted as unknown results on 23Feb2021, heart rate resulted as 120 bpm and around 150 on 23Feb2021, pulse resulted as high, it came down to 120 on an unspecified date, test resulted as negative on 23Feb2021, troponin resulted as unknown results on 23Feb2021 they drew troponins two times, they hydrated her with Lactated Ringers solutions, she consumed about 1,500 ccs. The clinical outcome of the events was unknown.  No follow-up attempts are possible, information about lot/batch number cannot be obtained.