fast beating (Fluttering); tired; Muscle Pain; Extreme Pain from (L) shoulder to elbow joint pains/extreme shoulder pains; Difficulty breathing; Fast heart beat; Weakness; Chest Pain/ extreme chest pain; "Patient EKG shows R B.B.B.",; This spontaneous case was reported by a consumer and describes the occurrence of DYSPNOEA (Difficulty breathing), HEART RATE INCREASED (Fast heart beat), ASTHENIA (Weakness), CHEST PAIN (Chest Pain/ extreme chest pain) and BUNDLE BRANCH BLOCK RIGHT ("Patient EKG shows R B.B.B.",) in an 87-year-old patient of an unknown gender who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 014F21A and 062E21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     No Medical History information was reported.   On 24-Aug-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 21-Sep-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On an unknown date, the patient experienced DYSPNOEA (Difficulty breathing), HEART RATE INCREASED (Fast heart beat), ASTHENIA (Weakness), CHEST PAIN (Chest Pain/ extreme chest pain), BUNDLE BRANCH BLOCK RIGHT ("Patient EKG shows R B.B.B.",), CARDIAC FLUTTER (fast beating (Fluttering)), FATIGUE (tired), MYALGIA (Muscle Pain) and ARTHRALGIA (Extreme Pain from (L) shoulder to elbow joint pains/extreme shoulder pains). The patient was treated with ASPIRIN [ACETYLSALICYLIC ACID] for Adverse event, at a dose of 81 mgs. At the time of the report, DYSPNOEA (Difficulty breathing), HEART RATE INCREASED (Fast heart beat), ASTHENIA (Weakness), CHEST PAIN (Chest Pain/ extreme chest pain), BUNDLE BRANCH BLOCK RIGHT ("Patient EKG shows R B.B.B.",), CARDIAC FLUTTER (fast beating (Fluttering)), FATIGUE (tired), MYALGIA (Muscle Pain) and ARTHRALGIA (Extreme Pain from (L) shoulder to elbow joint pains/extreme shoulder pains) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Cardiac stress test: good (normal) good. On an unknown date, Electrocardiogram: good (normal) good. On an unknown date, Heart rate: fast (High) Fast.         It was reported that Patient used to walk (1) mile daily, worked in garden, walk the dogs, etc.  This case concerns an 87-year-old patient of an unknown gender with no relevant medical history, who experienced the unexpected adverse events of special interest Bundle Branch Block Right and Cardiac Flutter. The event occurred on an unknown date after receiving the second dose of mRNA-1273 Vaccine. The re-challenge was not applicable since only information about the second dose was disclosed. The benefit-risk relationship of mRNA-1273 Vaccine is not affected by this report.; Sender's Comments: This case concerns an 87-year-old patient of an unknown gender with no relevant medical history, who experienced the unexpected adverse events of special interest Bundle Branch Block Right and Cardiac Flutter. The event occurred on an unknown date after receiving the second dose of mRNA-1273 Vaccine. The rechallenge was not applicable since only information about the second dose was disclosed. The benefit-risk relationship of mRNA-1273 Vaccine is not affected by this report.