Ventricular Tachycardia (VTach); Atrial Fibrillation (AFib); Hot to touch; she has had abnormal level of her liver function; Painful at the Injection site; Irregular heart beat; Vitamin D decreased; Platelet count decreased; Arm was swollen; Redness; thought it was cellulitis; This spontaneous case was reported by a patient and describes the occurrence of VENTRICULAR TACHYCARDIA (Ventricular Tachycardia (VTach)) and ATRIAL FIBRILLATION (Atrial Fibrillation (AFib)) in a 65-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 038K20A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     The patient's past medical history included Overweight. Concomitant products included DIPHTHERIA VACCINE from 09-Mar-2021 to an unknown date for an unknown indication.    On 31-Jan-2021, the patient received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. In February 2021, the patient experienced VACCINATION SITE CELLULITIS (thought it was cellulitis), VACCINATION SITE SWELLING (Arm was swollen) and VACCINATION SITE ERYTHEMA (Redness). On 07-Mar-2021, the patient experienced VENTRICULAR TACHYCARDIA (Ventricular Tachycardia (VTach)) (seriousness criteria hospitalization and medically significant), ATRIAL FIBRILLATION (Atrial Fibrillation (AFib)) (seriousness criteria hospitalization and medically significant), PLATELET COUNT DECREASED (Platelet count decreased) and VITAMIN D DECREASED (Vitamin D decreased). On 17-May-2021, the patient experienced HEART RATE IRREGULAR (Irregular heart beat). On an unknown date, the patient experienced VACCINATION SITE WARMTH (Hot to touch), HEPATIC FUNCTION ABNORMAL (she has had abnormal level of her liver function) and VACCINATION SITE PAIN (Painful at the Injection site). The patient was treated with CEFALEXIN MONOHYDRATE (KEFLEX [CEFALEXIN MONOHYDRATE]) ongoing since an unknown date for Vaccination site cellulitis, at a dose of 1 dosage form; MUPIROCIN ongoing since an unknown date for Vaccination site cellulitis, at a dose of 1 dosage form; ACRIVASTINE (BENADRYL ALLERGY RELIEF) ongoing since an unknown date for Adverse event, at a dose of 1 dosage form; APIXABAN (ELIQUIS) ongoing since an unknown date for Atrial fibrillation, at a dose of 1 dosage form, blood thinner; VITAMIN D NOS ongoing since an unknown date for Vitamin deficiency, at a dose of 1 dosage form and METOPROLOL ongoing since an unknown date for Adverse event, at a dose of 25 mg as required. On 07-Mar-2021, VENTRICULAR TACHYCARDIA (Ventricular Tachycardia (VTach)) and ATRIAL FIBRILLATION (Atrial Fibrillation (AFib)) had resolved. At the time of the report, HEART RATE IRREGULAR (Irregular heart beat), VACCINATION SITE CELLULITIS (thought it was cellulitis) and VITAMIN D DECREASED (Vitamin D decreased) had resolved and VACCINATION SITE WARMTH (Hot to touch), PLATELET COUNT DECREASED (Platelet count decreased), HEPATIC FUNCTION ABNORMAL (she has had abnormal level of her liver function), VACCINATION SITE PAIN (Painful at the Injection site), VACCINATION SITE SWELLING (Arm was swollen) and VACCINATION SITE ERYTHEMA (Redness) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 29-Apr-2021, Echocardiogram: normal (normal) Test was performed on 16th March. On 29-Apr-2021, Heart rate: 130 or 140 (abnormal) Irregular pulse of 130 or 140. On 29-Apr-2021, Platelet count: 105,000 (abnormal) abnormal platelet level 105,000 on 7th March 2021 and low (abnormal) platelets count of 137,000 [normal level: 150,000-450,000] on 6-JUN-2021. On 29-Apr-2021, Troponin: 0.0033 (normal) 0.0033 [Normal: lower than 0.045].     For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   Patient went on to consult with her HCP thought of vaccination site was Cellulitis and it had Infiltrated the tissue at injection site.  Patient stated that she has had abnormal level of her liver function. The doctor performed a CAT scan and blood work and was diagnosed with Arrhythmia with Atrial Fibrillation and Ventricular Tachycardia.  On 09 Mar 2021, Patient was told to get the Pneumonia Vaccine along with DPT [diphtheria] vaccine. Patient received both of the vaccine in each arm. Patient had no idea which vaccine was given on the left arm. But again her left arm was swollen, redness, and painful.  She stated that in the past never had blood work done. But since the incident, her blood work had been abnormal. Particularly her platelets had been dropping. So patient said her blood work was done on March 7, March 9, April 29th (platelets level were 105,000 then normal), May 3, May 12, and May 17th. She had followed up with Hematologist who  informed her that this go eventually go away and it can come back to normal level.  She also confirmed that they did not take any medicine or over the counter medicine prior to receiving COVID-19 vaccine and said that her HCP are looking into to see if she can potentially get the 3rd dose or not of the Moderna COVID-19 vaccine.  Patient stated that she had risk factor of Over weight.  This case concerns a 65-year-old female patient with no details on previous relevant medical history, who experienced the unexpected serious events of Atrial fibrillation and Ventricular tachycardia and the non-serious AESI of Platelet count  decreased with other associated non serious events after (mRNA- 1273 vaccine / Moderna COVID-19 Vaccine). The onset of the events occurred approximately 1 month and 8 days after the second dose. The rechallenge is not applicable, since the events occurred after the second dose. The benefit-risk relationship of vaccine is not affected by this report.   This case was linked to MOD-2021-330876 (Patient Link).; Sender's Comments: This case concerns a 65-year-old female patient with no details on previous relevant medical history, who experienced the unexpected serious events of Atrial fibrillation and Ventricular tachycardia and the non-serious AESI of Platelet count  decreased with other associated non serious events after (mRNA- 1273 vaccine / Moderna COVID-19 Vaccine). The onset of the events occurred approximately 1 month and 8 days after the second dose. The rechallenge is not applicable, since the events occurred after the second dose. The benefit-risk relationship of vaccine is not affected by this report.