Diagnosed with Premature Atrial Contraction after booster; High Blood Pressure 182/ unknown mmHg; Chest Pain; Weakness; Dizziness; This spontaneous case was reported by a consumer and describes the occurrence of SUPRAVENTRICULAR EXTRASYSTOLES (Diagnosed with Premature Atrial Contraction after booster), HYPERTENSION (High Blood Pressure 182/ unknown mmHg), CHEST PAIN (Chest Pain), ASTHENIA (Weakness) and DIZZINESS (Dizziness) in a 74-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 058F21A, 013M20A and 022M20A) for COVID-19 vaccination.     No Medical History information was reported.   On 03-Feb-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 03-Mar-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 18-Nov-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. In December 2021, the patient experienced SUPRAVENTRICULAR EXTRASYSTOLES (Diagnosed with Premature Atrial Contraction after booster), HYPERTENSION (High Blood Pressure 182/ unknown mmHg), CHEST PAIN (Chest Pain), ASTHENIA (Weakness) and DIZZINESS (Dizziness). The patient was treated with METOPROLOL TARTRATE (oral) for Blood pressure high and Chest pain, at a dose of 25 milligram twice a day. At the time of the report, SUPRAVENTRICULAR EXTRASYSTOLES (Diagnosed with Premature Atrial Contraction after booster), HYPERTENSION (High Blood Pressure 182/ unknown mmHg), CHEST PAIN (Chest Pain), ASTHENIA (Weakness) and DIZZINESS (Dizziness) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In December 2021, Heart rate: increased heart rate (High) increased Heart rate.         No concomitant medication was reported. Patient states that one month after the booster, she had increased Heart rate and chest pain. She ended up in the emergency room  and diagnosed with Premature Atrial Contraction after booster. She states that she had Dizziness, Weakness, increased Heart Rate (unknown #), and High Blood Pressure 182/ unknown mmHg. Patient stated that she does not have a medical history of any type of heart disease and never had high blood pressure. She did not take medications prior to vaccination. She was released from  ER on the same day with a prescription for a Beta blocker that was Metoprolol Tartrate 25mg (1/2 PO BID) and she was wearing a heart monitor.  Company comment: This case concerns a 74-year-old female patient, with no reported medical history, who experienced the non-serious, unexpected AESI event of supraventricular extrasystoles 1 month after the third dose mRNA 1273 COVID-19 vaccine. One month after the booster dose, patient had increased heart rate and chest pain. She went to the emergency room and was diagnosed with Premature Atrial Contraction. Patient also experienced dizziness, asthenia and high blood pressure.  The benefit-risk relationship of mRNA 1273 vaccine is not affected by this report.; Sender's Comments: This case concerns a 74-year-old female patient, with no reported medical history, who experienced the non-serious, unexpected AESI event of supraventricular extrasystoles 1 month after the third dose mRNA 1273 COVID-19 vaccine. One month after the booster dose, patient had increased heart rate and chest pain. She went to the emergency room and was diagnosed with Premature Atrial Contraction. Patient also experienced dizziness, asthenia and high blood pressure.  The benefit-risk relationship of mRNA 1273 vaccine is not affected by this report.