Myocarditis and Other Cardiovascular Complications of the mRNA-Based COVID-19 Vaccines.

Cardiovascular complications following the receipt of mRNA-based (Pfizer-BioNTech and Moderna) coronavirus disease 2019 (COVID-19) vaccines have not yet been described. In this case series, we describe two patients with clinically suspected myocarditis, one patient with stress cardiomyopathy, and two patients with pericarditis after receiving an mRNA-based COVID-19 vaccine. The two patients with clinically suspected myocarditis were otherwise healthy young men who presented with acute substernal chest pressure and/or dyspnea after receiving the second dose of the vaccine and were found to have diffuse ST elevations on electrocardiogram (ECG), elevated cardiac biomarkers and inflammatory markers, and mildly reduced left ventricular (LV) function on echocardiography. Both patients met the modified Lake Louise Criteria for acute myocarditis by cardiac magnetic resonance imaging. We subsequently discuss a case of a 60-year-old woman with known coronary artery disease (CAD) and previously normal LV function, who presented with new exertional symptoms, ECG changes, and apical akinesis following the second dose of the vaccine, and was diagnosed with a stress cardiomyopathy. Finally, we describe two patients with pericarditis who presented with chest pain, elevated inflammatory markers, and pericardial effusions after receiving the vaccine. Overall, this case series describes the first reported cases of myocarditis, stress cardiomyopathy, and pericarditis after receiving an mRNA-based COVID-19 vaccine.