Abstract
Electrocardiographic alterations of ventricular repolarization have already been reported in cases of myocarditis following coronavirus disease-19 (COVID-19) vaccine, but it is not clear how long they persist. A 21-year-old female presented with chest discomfort and diffuse myalgia a week after receiving the first dose of a messenger RNA (mRNA) COVID-19 vaccine. The 12 leads standard electrocardiogram unveiled negative T waves in anterior and inferior leads, while her troponin-I values resulted in the upper limit. A mild form of post-COVID-19 vaccine myocarditis was diagnosed since the echocardiogram excluded major systolic alterations and pericardial effusions. The patient refused hospitalization, but luckily, she remained hemodynamically stable, presenting a quick clinical response to oral non-steroidal anti-inflammatory therapy. However, the electrocardiographic abnormalities required weeks for resolving. In our case, the later normalization of electrocardiographic anomalies was not associated with an ominous clinical course.