Lessons Learnt from Case Series of Out-of-hospital Cardiac Arrest and Unexpected Death after COVID-19 Vaccination.

Vaccination against COVID-19 has raised concerns about myocarditis in young men, as out-of-hospital cardiac arrest (OHCA) or sudden death after vaccination has been reported sporadically. Common features of these cases are occurrence in young men, within a few weeks after vaccination, in patients with no structural heart diseases. Cases of unexplained nocturnal death showed fibrotic or hypertrophied myocardium, and one case of OHCA presented ventricular fibrillation (VF) triggered by a prominent J wave on an automated external defibrillator and histopathologic findings compatible with myocarditis. Both myocarditis and J waves are prevalent in young men, and these cases imply that myocarditis augments J waves, which trigger VFs, and primary electrical disorders are a leading cause of death. To prevent such issues, artificial intelligence (AI)-assisted interpretation of historical electrocardiogram findings may help predict future J wave formation leading to VF, as digital electrocardiogram (ECG) findings are well suited for AI interpretation.