Congestive heart failure; This is a spontaneous report received from a contactable consumer (Patient). A 60-years-old female patient received second dose of BNT162b2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE, Batch/Lot Number: Unknown), via an unspecified route of administration, administered in Arm Right on 30Mar2021 11:00 (at the age of 60-years-old) as DOSE 2, SINGLE for covid-19 immunisation. Medical history included atrial fibrillation, cardiac disorder from an unknown date and unknown if ongoing. The patient's concomitant medications were not reported. The patient previously took first dose of bnt162b2 (Lot: unknown) on 10Mar2020 at 11:00 PM in the right arm for COVID-19 immunisation and experienced shortness of breath. The patient experienced congestive heart failure on Jun2021. The events assessed as serious (medically significant). Call was from two sisters, a 57 year old female and a 60 year old female. One received her Pfizer Covid-19 vaccine on 22Jun2021 and started experiencing shortness of breath and dyspnea. The other sister received the Pfizer Covid-19 vaccine on 10Mar2021 and starting experiencing shortness of breath as well but attributed to her history of atrial fibrillation initially. Both are wondering if anyone else was having these complaints and if there are any recommendations for the complaints. Patient mentioned while providing family history, her sister had the COVID 19 vaccination and also had shortness of breath. Adds her sister got her vaccination in Mar2021 but she does not had her card with her. She also had shortness of breath and was still having it. She did not put two and two and together until her sister had it. This was a clone report was created to document the sister's experience. Patient adds the shortness of breath that started in Mar2021. States she had previously been off work for a year with A-Fib but she was doing really well, she had started walking around the block and everything. Reports she was unsure of exactly when she noticed the shortness of breath. She went from the car to the store and she was short of breath so she went to the emergency room to get it checked but everything was good. Mentions she was also diagnosed with congestive heart failure about a month ago. After she went to the emergency room she just went back and forth to her doctors. The lung doctor said she was okay and the heart doctor, too. She kept going to the doctor because it did not dawn on her that the shortness of breath might be related to the vaccination until her sister got her vaccination and had the shortness of breath. Now she believes she noticed the shortness of breath after the first dose. Mentions she has the emergency room records and her vaccination card at home to verify her information. Adds she was talking to a guy at the bus station and he had shortness of breath too. She does not know this person and declined to report regarding the guy at the bus station. Patient visited Emergency Room, but not admitted. Patient visited physician Office. The patient underwent lab tests and procedures which included blood test: good, chest x-ray: good, electrocardiogram: good on More information available (Y/N): No. The outcome of the events was reported as unknown.   Information on the Batch/lot number has been requested.; Sender's Comments: Linked Report(s) : US-PFIZER INC-2021829874 same reporter/drug/event, different patient