I had a level 2 blockage; Several hours later my heart stopped twice and I was resusciated.; The next morning I had shortness of breath after going up the stairs but it went away right away; My blood press was 194/120; On Sat., July 1 my pulse measured 30; I felt fatigued for about 2 weeks; This spontaneous case was reported by a patient and describes the occurrence of CARDIAC ARREST (Several hours later my heart stopped twice and I was resusciated.) and ATRIOVENTRICULAR BLOCK SECOND DEGREE (I had a level 2 blockage) in a 74-year-old female patient who received mRNA-1273 BIVALENT .222 (MODERNA COVID-19 VACCINE, BIVALENT (ORIGINAL AND OMICRON BA.4/BA.5)) (batch no. AS7463E) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.     No Medical History information was reported.    On 21-Jun-2023, the patient received sixth dose of mRNA-1273 BIVALENT .222 (MODERNA COVID-19 VACCINE, BIVALENT (ORIGINAL AND OMICRON BA.4/BA.5)) (Intramuscular) 1 dosage form. On 01-Jul-2023, the patient experienced ATRIOVENTRICULAR BLOCK SECOND DEGREE (I had a level 2 blockage) (seriousness criterion hospitalization) and HEART RATE DECREASED (On Sat., July 1 my pulse measured 30). On 02-Jul-2023, the patient experienced DYSPNOEA (The next morning I had shortness of breath after going up the stairs but it went away right away) and BLOOD PRESSURE INCREASED (My blood press was 194/120). In July 2023, the patient experienced CARDIAC ARREST (Several hours later my heart stopped twice and I was resusciated.) (seriousness criteria hospitalization and medically significant). On an unknown date, the patient experienced FATIGUE (I felt fatigued for about 2 weeks). The patient was hospitalized from sometime in July 2023 to 05-Jul-2023 due to ATRIOVENTRICULAR BLOCK SECOND DEGREE and CARDIAC ARREST. The patient was treated with Surgery (Got a temporary pacemaker. On July 4, got a permanent pacemaker.) for Cardiac arrest. In July 2023, CARDIAC ARREST (Several hours later my heart stopped twice and I was resusciated.), ATRIOVENTRICULAR BLOCK SECOND DEGREE (I had a level 2 blockage) and DYSPNOEA (The next morning I had shortness of breath after going up the stairs but it went away right away) had resolved. At the time of the report, BLOOD PRESSURE INCREASED (My blood press was 194/120) and HEART RATE DECREASED (On Sat., July 1 my pulse measured 30) outcome was unknown and FATIGUE (I felt fatigued for about 2 weeks) had resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In April 2023, Electrocardiogram: I had a normal ECG in April.. On 01-Jul-2023, Heart rate: On Sat, July 1 my pulse measured 30. On 02-Jul-2023, Blood pressure measurement: Sunday evening I got a new blood pressure cuff and it said my blood press was 194/120. On 02-Jul-2023, Heart rate: Sunday evening pulse was 30. On an unknown date, Electrocardiogram: They did an ECG and said it looked like I had a level 2 blockage.     For mRNA-1273 BIVALENT .222 (MODERNA COVID-19 VACCINE, BIVALENT (ORIGINAL AND OMICRON BA.4/BA.5)) (Intramuscular), the reporter did not provide any causality assessments.   Concomitant medication was not provided. On July 1 patient pulse was 30, she thought the machine was malfunctioning. On Sunday evening, her blood press was 194/120 and pulse was 30. Hence went to acute care and was taken to the emergency room. Patient was released on July 5 and was feeling normal. Patient didn't blame the vaccine but it seemed odd to her that the fatigue seemed to start soon after the vaccine and then the rest followed 2 weeks later. Patient never had any heart problems or irregulat heart beat before.  Treatment information was not reported. Company comment This spontaneous case concerns a 74-year-old female patient with no medical history reported, who experienced the unexpected, serious (medically significant and hospitalization) event of cardiac arrest and the unexpected serious (hospitalization) AESI of Atrioventricular block second degree.  Atrioventricular block second degree occurred 10 days after the sixth dose of mRNA-1273.222 (BA.4/BA.5). It was reported that the patient felt fatigued for about 2 weeks and her pulse was 30 and her blood pressure was 194/120, so she was taken to the emergency room and hospitalized. They did an Electrocardiogram and said it looked like a level 2 blockage. The patient's heart stopped twice, and she was resuscitated. She was treated with a temporary pacemaker and then got a permanent pacemaker. No further clinical information was provided. The events cardiac arrest could be associated with Atrioventricular block second degree. Atrioventricular block second degree could be associated with the non-serious events of dyspnoea, fatigue, heart rate decreased, and blood pressure increased. The benefit-risk relationship of mRNA-1273.222 (BA.4/BA.5) vaccine is not affected by this report.