when she was even sitting her heart rate went up and down; This spontaneous case was reported by a consumer and describes the occurrence of HEART RATE IRREGULAR (when she was even sitting her heart rate went up and down) in a 68-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 050c21a) for COVID-19 vaccination.     The patient's past medical history included Thyroidectomy (thyroid removed). Concurrent medical conditions included Graves' disease and Drug allergy (Tapazole). Concomitant products included LEVOTHYROXINE for an unknown indication.    On 16-Jun-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. In 2021, the patient experienced HEART RATE IRREGULAR (when she was even sitting her heart rate went up and down). At the time of the report, HEART RATE IRREGULAR (when she was even sitting her heart rate went up and down) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In 2021, Heart rate: irregular irregular.     The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown) was unknown.       The patient's height was reported as under 5 feet 10 inches. The patient has not diagnosed with COVID 19 or tested for COVID. The patient had no medical history relating to mentioned adverse events Acute and Chronic illnesses at the time of vaccination. The patient stated there were no history in her family for reported events and she never had any issues on that. No other vaccines were given within 1 month prior to Moderna COVID-19 vaccine. The patient has not experienced a similar event in the past.. The patient monitors her heart rate with her watch. No treatment drug was reported.  Company Comment: This spontaneous case concerns a 68-year-old female patient with relevant medical history of Graves' disease with post thyroidectomy state and concomitantly taking levothyroxine, who experienced the unexpected, non-serious adverse event of special interest of Heart rate irregular, that occurred after receiving first dose of mRNA-1273 vaccine. Patient took medical care for the treatment of event; however, further details on clinical course, diagnostic tests performed, and treatment specifics were not provided. Outcome of the event Heart rate irregular was reported as not recovered. Hypothyroid state with concomitant use levothyroxine remains as strong confounder. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.   This case was linked to MOD-2022-537903 (Patient Link).; Sender's Comments: This spontaneous case concerns a 68-year-old female patient with relevant medical history of Graves' disease with post thyroidectomy state and concomitantly taking levothyroxine, who experienced the unexpected, non-serious adverse event of special interest of Heart rate irregular, that occurred after receiving first dose of mRNA-1273 vaccine. Patient took medical care for the treatment of event; however, further details on clinical course, diagnostic tests performed, and treatment specifics were not provided. Outcome of the event Heart rate irregular was reported as not recovered. Hypothyroid state with concomitant use levothyroxine remains as strong confounder. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.