Dehydrated; Collapsed; Cardiac death/the patient woke up and then grab it's chest and collapsed; Started having heart issues; Chest pain; Lose it's appetite; Thirsty; Short of breath/got very winded; Fatigue/ very tired; This spontaneous case was reported by a consumer (subsequently medically confirmed) and describes the occurrence of CARDIAC DEATH (Cardiac death/the patient woke up and then grab it's chest and collapsed), DEHYDRATION (Dehydrated) and CIRCULATORY COLLAPSE (Collapsed) in a 66-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concomitant products included CHLORTHALIDONE, LOSARTAN POTASSIUM, MELOXICAM, METOPROLOL SUCCINATE, PANTOPRAZOLE SODIUM SESQUIHYDRATE (PANTOPRAZOLE SODIUM), TAMSULOSIN HYDROCHLORIDE (TAMSULOSIN HCL), RIVAROXABAN (XARELTO), AMLODIPINE BESILATE (AMLODIPINE BESYLATE) and TADALAFIL for an unknown indication.   On 01-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 01-Apr-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. In April 2021, the patient experienced DEHYDRATION (Dehydrated) (seriousness criterion hospitalization), CARDIAC DISORDER (Started having heart issues), CHEST PAIN (Chest pain), DECREASED APPETITE (Lose it's appetite), THIRST (Thirsty), DYSPNOEA (Short of breath/got very winded) and FATIGUE (Fatigue/ very tired). On an unknown date, the patient experienced CIRCULATORY COLLAPSE (Collapsed) (seriousness criterion medically significant). The patient died on 10-Apr-2021. The reported cause of death was Cardiac death. An autopsy was not performed. At the time of death, DEHYDRATION (Dehydrated), CIRCULATORY COLLAPSE (Collapsed), CARDIAC DISORDER (Started having heart issues), CHEST PAIN (Chest pain), DECREASED APPETITE (Lose it's appetite), THIRST (Thirsty), DYSPNOEA (Short of breath/got very winded) and FATIGUE (Fatigue/ very tired) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Electrocardiogram: inconclusive (Inconclusive) Inconclusive and inconclusive (Inconclusive) Inconclusive.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   Action taken with the mRNA-1273 vaccine due to the events was not applicable.  The reporter informed that the patient had received both doses of mRNA-1273 vaccine. He first lost his appetite and started feeling thirsty on the following day after vaccination, which worsened progressively for the next five days. The patient then started having chest pain, was short of breath and experienced fatigue. He got very winded when he went to the bathroom and felt very tired for the next two days, When he went to the hospital, the doctor said that he would need to be admitted if he doesn't feel well. On a Wednesday, the patient went to the hospital and an ECG was done. The reporter informed that when the doctor compared it with an ECG from few days before, he could not believe it was of the same patient's. The patient was taken to the ER (emergency room) and was them transferred to ICU (intensive care unit) as he was dehydrated. Dehydration was treated and at the time the patient started having heart issues. By Friday, the patient started doing better and the doctor discussed discharging him. On Saturday, when the patient woke up he grabbed his chest and collapsed. The reporter informed that they were not able to get an autopsy but the death was assumed to be cardiac death. It was reported that the patient passed away approximately nine days after receiving the second dose of the vaccine. The reporter further informed that the patient was in good health and had a full 'cardiac work' prior to his vaccination.  Company comment: Very limited information regarding this event has been provided at this time. Details regarding medical history and course in the hospital is required for further evaluation.; Sender's Comments: Very limited information regarding this event has been provided at this time. Details regarding medical history and course in the hospital is required for further evaluation.; Reported Cause(s) of Death: Cardiac death