I was depleted; Dizzy; extreme fatigue; erratic heartbeat; This is a spontaneous report from a contactable consumer (patient) reported for herself that a 78-year-old non-pregnant female patient received first dose of BNT162B2 (Pfizer-Biontech COVID-19 Vaccine, Solution for injection, lot number: EL9261, expiry date: Unknown), via an unknown route of administration in left arm on 05Feb2021 at 11:45 (at the age of 78-year-old) as single for COVID-19 immunisation at hospital. The patient's medical history included pulmonary embolism from 2012 to 2014. She had known allergies of penicillium, sulfa and eggplant. The patient stated that she was on blood pressure medicine, she assumed that was hypertension. Concomitant medications included irbesartan (IRBESARTAN), warfarin (WARFARIN) and pravastatin (PRAVASTATIN); all were taken for an unknown indication from an unknown date and unknown if ongoing. Daily Vitamin and other supplements were taken in two weeks. No other vaccine in four weeks. On 08Feb2021 at 21:00, the patient experienced dizzy, extreme fatigue, erratic heartbeat. On an unknown date, she was depleted. Patient stated, "5 days after I had my first shot of Pfizer COVID-19 vaccine, I became dizzy and totally fatigued. The patient was very high energy person probably on a scale of 1 to 10, I am 15, usually just out there doing stuff for everybody. But I would say on a scale of 1 to 10 now, just I was depleted. Yesterday, I had a good day but that's the first one in about 10 days. I get up and I am just fatigued after 20 minutes had to go sit on the couch or the recliner, get up and do something and sit again. And so, I ended up, I could tell after several days, I was just kind of trying to get in touch with my own body, I had an erratic heartbeat. So, I finally went to the emergency room and they ran multiple tests and they said - Yes, you do have erratic but don't worry about it, it's not bad, it's one of those common things. But they did put me on a heart monitor for 10 days. I carried this little phone thing in my pocket, and I have a patch on my chest that reports to the phone. Anyway, so they did blood test, they did a number of blood tests. They ruled out any enzyme problem with the heart. They did a chest X-ray and felt that they ruled out anything that could be a pulmonary fibrosis. When I got there, they did, I had a COVID test, a rapid walk-in test about 4 days before and it was negative. But they did another rapid test and that was negative. And then they decided to do the more extended tests, it took like a whole day to get the results and it was also negative. So, I had 3 negative COVID tests in the last 6 days. So that's basically where I am and I am just concerned because this coming Friday, I am to get my second COVID shot and I am wondering if this was related, how do we proceed." The patient visited due to adverse event doctor or other healthcare professional office/clinic, emergency room/department or urgent care. No Covid prior vaccination. On 10Feb2021, the patient had covid test post vaccination by nasal swab which resulted as negative. On 10Feb2021, she had chest x-ray, electrocardiogram, blood test with unknown results, while heartbeat (heart monitor) resulted as erratic. Received treatment for adverse events. The outcome of the events was not recovered, while the outcome of the remaining event "I was depleted" was unknown.  No follow-up attempts are possible. No further information is expected.