Cardiac imaging procedure abnormal; Chest pain; Diastolic dysfunction; Ejection fraction normal; Magnetic resonance imaging heart; Pleuritic pain; Troponin I increased; This case was received via Regulatory Authority (Reference number: 1939721) on 28-Dec-2021 and was forwarded to Moderna on 28-Dec-2021.    This regulatory authority case was reported by an other health care professional and describes the occurrence of CARDIAC IMAGING PROCEDURE ABNORMAL (Cardiac imaging procedure abnormal), CHEST PAIN (Chest pain), DIASTOLIC DYSFUNCTION (Diastolic dysfunction), EJECTION FRACTION NORMAL (Ejection fraction normal), MAGNETIC RESONANCE IMAGING HEART (Magnetic resonance imaging heart), PLEURITIC PAIN (Pleuritic pain) and TROPONIN I INCREASED (Troponin I increased) in a 26-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for an unknown indication.     The patient's past medical history included Attention deficit hyperactivity disorder.    On 06-Dec-2021, the patient received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 07-Dec-2021, the patient experienced CARDIAC IMAGING PROCEDURE ABNORMAL (Cardiac imaging procedure abnormal) (seriousness criterion hospitalization), CHEST PAIN (Chest pain) (seriousness criterion hospitalization), DIASTOLIC DYSFUNCTION (Diastolic dysfunction) (seriousness criterion hospitalization), EJECTION FRACTION NORMAL (Ejection fraction normal) (seriousness criterion hospitalization), MAGNETIC RESONANCE IMAGING HEART (Magnetic resonance imaging heart) (seriousness criterion hospitalization), PLEURITIC PAIN (Pleuritic pain) (seriousness criterion hospitalization) and TROPONIN I INCREASED (Troponin I increased) (seriousness criterion hospitalization). At the time of the report, CARDIAC IMAGING PROCEDURE ABNORMAL (Cardiac imaging procedure abnormal), CHEST PAIN (Chest pain), DIASTOLIC DYSFUNCTION (Diastolic dysfunction), EJECTION FRACTION NORMAL (Ejection fraction normal), MAGNETIC RESONANCE IMAGING HEART (Magnetic resonance imaging heart), PLEURITIC PAIN (Pleuritic pain) and TROPONIN I INCREASED (Troponin I increased) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 09-Dec-2021, Magnetic resonance imaging heart: abnormal (abnormal) LVEF 55%, patchy LGE, T1 1100 msec, no effusion, no pericardial enhancement.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   Other medication use information was provided by reporter that includes Atomoxetine 10mg once a day and MVI . No treatment information was provided. After vaccination Patient was experience with chest pain, and pleuritic. within 24 hours. The laboratory data was done that include troponin and result was found to be I0486 and also MRI was done and result was found LGE and abnormal T1 1100 msec.; Sender's Comments: This case concerns a 26year-old male patient, with medical history of Attention deficit hyperactivity disorder, who experienced the serious unexpected event(s) of Cardiac imaging procedure abnormal, chest pain, diastolic dysfunction, ejection fraction normal, pleuritic pain troponin increased and Magnetic resonance imaging heart. The event(s) started occurring approximately within 1 day(s) after the 3rd dose of mRNA-1273, Moderna COVID-19 Vaccine. The rechallenge was considered NA. The benefit-risk relationship of mRNA-1273, Moderna COVID-19 Vaccine is not affected by this report.