Pathological Evidence for SARS-CoV-2 as a Cause of Myocarditis

JACC Review Topic of the Week

Rika Kawakami, MD; Atsushi Sakamoto, MD; Kenji Kawai, MD; Andrea Gianatti, MD; Dario Pellegrini, MD; Ahmed Nasr, MD; Bob Kutys, PA; Liang Guo, PHD; Anne Cornelissen, MD; Masayuki Mori, MD; Yu Sato, MD; Irene Pescetelli, MD; Matteo Brivio, MD; Maria Romero, MD; Giulio Guagliumi, MD; Renu Virmani, MD; Aloke V. Finn, MD


J Am Coll Cardiol. 2021;77(3):314-325. 

In This Article

The Authors' Position on Usefulness of EMB in Cases of Suspected COVID-19-induced Myocarditis

The EMB procedure itself comes with inherent risks, including cardiac perforation, pericardial tamponade, bleeding, and so on, although these have declined with the use of flexible bioptomes with smaller jaws. The incidence of complications was 1.2%, with perforation occurring in 0.42% and death in 0.03%.[16] The reason for EMB should be based upon the anticipated yield of the disorder (presumed probability and risk of sampling error) and the presence of an effective therapy. Certainly, the procedure should only be recommended in cases where benefits of the information obtained outweighs the potential risks of the procedure. The preponderance of autopsy and EMB evidence to date in cases of suspected myocarditis after COVID-19 infection suggests that myocarditis is an uncommon diagnosis. Moreover, the limited sampling of the heart (confined usually to the right ventricular septum) combined with the rarity of COVID-19 myocarditis makes diagnostic yield very unlikely, as has been shown in published cases where EMB has been conducted in cases of suspected myocarditis in the setting of COVID-19 infection. Further complicating the issue of histological diagnosis is that the typical criteria for myocarditis based upon the presence of certain types of inflammation may be different in cases of COVID-19 where very ill patients tend to have lymphopenia.[34] It remains unclear to what extent lymphocytic infiltration should be expected in these cases (as it is in typical myocarditis). Moreover, the therapeutic implications are even less clear given there is no data supporting the effectiveness of particular therapies for myocarditis in the setting of COVID-19. Thus, at present, the authors believe EMB should not be routinely performed in such cases and should perhaps be reserved for worst case scenarios, such as patients with new-onset fulminant heart failure with hemodynamic compromise in the setting of documented COVID-19 infection, and the absence of coronary artery disease.