BACKGROUND Since Emergency Use Authorization of COVID-19 vaccines in December 2020, more is becoming known about their adverse effects. Growing numbers of myopericarditis cases after COVID-19 vaccination are being reported, mostly in younger adults. While most of these patients have recovered rapidly and without complications, it is still unclear whether patients who are older and have greater cardiac dysfunction secondary to myopericarditis will also experience the same recovery. CASE REPORT We report the case of a middle-aged man with myopericarditis and significant left ventricular dysfunction after the second dose of the Pfizer/BioNTech BNT162b2 COVID-19 vaccine. He presented several days after vaccination, and with non-steroidal anti-inflammatory treatment, he quickly recovered ventricular function, and symptoms resolved within 1 week after vaccination. CONCLUSIONS Vaccines are a key tool in combating the COVID-19 pandemic, yet many people are hesitant to seek vaccination, perhaps for fear of adverse events. Our report of a middle-aged patient with significant left ventricular dysfunction, who still experienced rapid recovery, should reassure the public about the safety of vaccines. Such rare adverse effects should not deter people from receiving COVID-19 vaccination.