Case Series Details Treatment of Myocarditis-Like Illness Following COVID-19 Vaccination

The American Heart Association is calling attention to a new study detailing the treatment of temporary myocarditis among patients who received a COVID-19 vaccine.

With perimyocarditis reported as a rare vaccination complication, the study reports a case series of 7 patients hospitalized with acute myocarditis-like illness following vaccination and provides insight into treatment of these patients, all of whom had symptoms resolve and were discharged within 4 days of admission.

“The clinical course of vaccine-associated myocarditis-like illness appears favorable, with resolution of symptoms in all patients. Given the potential morbidity of COVID-19 infection even in younger adults, the risk-benefit decision for vaccination remains highly favorable. Vaccine adverse event reporting remains of high importance and further studies are needed to elucidate the pathophysiological mechanism to potentially identify or prevent future occurrences,” said the researchers.

The case series, which was published in Circulation, details a cohort of 7 male patients treated at 2 medical centers in Virginia and Texas. All patients included in the study were under the age of 40 years, with the youngest being 19 years and the oldest being 39 years of age. All of the patients were White, with the exception of 1 Hispanic individual.

Among this cohort, only 1 patient reported a history of previous COVID-19 infection. All patients in the study were admitted to the hospital within 3-7 days of receiving a COVID-19 vaccine with sudden onset chest pain. Investigators noted 6 of these patients had received an mRNA vaccine from Moderna or Pfizer and 1 patient had received the adenovirus vaccine from Johnson & Johnson.

The presence of myocardial injury was confirmed in all patients through cardiac troponin I or elevated high sensitivity troponin testing. In ECG testing, patterns varied from normal to ST-segment elevation. Additionally, 3 patients underwent invasive coronary angiography but none had evidence of blockage. Investigators also noted no patients reported heart palpitations or signs of arrhythmia. Echocardiograms indicated left ventricular ejection ranged from 35-62% with 5 of the 7 patients having some degree of hypokinesis.

All patients underwent CMR between 3-37 days after vaccination. Investigators highlighted multi-focal subepicardial late gadolinium enhancement (LGE) was present in all 7 patients. Additionally, mid-myocardial LGE was observed in 4 of 7 patients and corresponding myocardial edema was found in 3 of 7. Investigators pointed out 2 patients who underwent CMR greater than 7 days from presentation showed no signs of edema and 1 patient’s images were limited by artifacts. An endomyocardial biopsy was performed in 1 patient and it returned no pathological evidence of myocarditis.

Investigators pointed out treatment of these patients varied and included beta-blockers and anti-inflammatory medications. The median length of hospital stay was 3±1 days and symptoms had resolved in patients by time of discharge.

A statement from the American Heart Association released around the publication of this study underlined myocarditis-like illnesses are a very rare complication observed among patients who receive a COVID-19 vaccine, with fewer than 1000 cases reported as of May 31, 2021, and nearly 312 million doses administered. The statement also noted the CDC plans to review suspected cases of myocarditis-like illnesses related to COVID-19 vaccinations at the ACIP meeting June 23-25.

This study, “Myocarditis Temporally Associated with COVID-19 Vaccination,” was published in Circulation.