Outcomes of COVID-19–Associated Acute Myocarditis

Quick Takes

  • The mean prevalence of acute myocarditis (AM) was 2.4 in 1,000 hospitalized patients with COVID-19 considering definitive/probable AM cases, and 4.1 in 1,000 if also considering possible AM cases.
  • Patients with pneumonia and COVID-19 AM were more likely to develop hemodynamic instability, require temporary mechanical circulatory support, and die compared with those without pneumonia and COVID-19.
  • Regarding treatment, the use of corticosteroids in patients with AM appeared safe, and in most cases, a rapid increase in LVEF was observed, although no causality can be inferred from these data.

Study Questions:

What are the prevalence, baseline characteristics, in-hospital management, and outcomes for patients with coronavirus disease 2019 (COVID-19)–associated acute myocarditis (AM)?

Methods:

The investigators assessed a total of 112 patients with suspected AM from 56,963 hospitalized patients with COVID-19 evaluated between February 1, 2020–April 30, 2021. Inclusion criteria were hospitalization for COVID-19 and a diagnosis of AM based on endomyocardial biopsy or increased troponin level plus typical signs of AM on cardiac magnetic resonance imaging. The authors identified 97 patients with possible AM, and among them, 54 patients with definite/probable AM supported by endomyocardial biopsy in 17 (31.5%) patients or magnetic resonance imaging in 50 (92.6%). They analyzed patient characteristics, treatments, and outcomes among all COVID-19–associated AM. The association between patient outcome (death or need for temporary mechanical circulatory support [t-MCS]) and AM with or without concurrent pneumonia was determined using univariate Cox regression analysis.

Results:

AM prevalence among hospitalized patients with COVID-19 was 2.4 per 1,000 hospitalizations considering definite/probable and 4.1 per 1,000 considering also possible AM. The median age of definite/probable cases was 38 years, and 38.9% were female. On admission, chest pain and dyspnea were the most frequent symptoms (55.5% and 53.7%, respectively). Thirty-one cases (57.4%) occurred in the absence of COVID-19–associated pneumonia. Twenty-one (38.9%) had a fulminant presentation requiring inotropic support or t-MCS. The composite of in-hospital mortality or t-MCS occurred in 20.4%. At 120 days, estimated mortality was 6.6%, 15.1% in patients with associated pneumonia versus 0% in patients without pneumonia (p = 0.044). During hospitalization, left ventricular ejection fraction (LVEF), assessed by echocardiography, improved from a median of 40% on admission to 55% at discharge (n = 47; p < 0.0001) similarly in patients with or without pneumonia. Corticosteroids were frequently administered (55.5%).

Conclusions:

The authors report that AM occurrence is estimated between 2.4 and 4.1 out of 1,000 patients hospitalized for COVID-19.

Perspective:

This study reports that mean prevalence of AM was 2.4 in 1,000 hospitalized patients with COVID-19 considering definitive/probable AM cases, and 4.1 in 1,000 if also considering possible AM cases. Of note, 57% of patients with AM had no significant acute lung injury caused by COVID-19. However, patients with pneumonia and COVID-19 and AM were more likely to develop hemodynamic instability, require t-MCS, and die compared with those without pneumonia and COVID-19. Regarding treatment, the use of corticosteroids in patients with AM appeared safe, and in most cases, a rapid increase in left ventricular ejection fraction was observed, although no causality can be inferred from these data.

Clinical Topics: Heart Failure and Cardiomyopathies, Noninvasive Imaging, Prevention, Acute Heart Failure, Echocardiography/Ultrasound, Magnetic Resonance Imaging

Keywords: Acute Lung Injury, Biopsy, Chest Pain, COVID-19, Diagnostic Imaging, Dyspnea, Echocardiography, Heart Failure, Hospital Mortality, Magnetic Resonance Imaging, Myocarditis, Patient Discharge, Pneumonia, Primary Prevention, Stroke Volume, Troponin, Ventricular Function, Left


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