Clinical features and outcomes of fulminant myocarditis revealed by nationwide cohort study

Myocarditis is an inflammatory disease of the myocardium often caused by viral infections or autoimmune disorders. Fulminant myocarditis (FM) is a rare and severe presentation of myocarditis characterized by hemodynamically unstable conditions requiring inotropes and/or mechanical circulatory support. The natural history of FM and its clinical features are incompletely understood because there is a lack of generalizable evidence.

A team of researchers at the Nara Medical University and National Cerebral and Cardiovascular Center performed a nationwide cohort study of patients with histologically proven FM, in 235 cardiovascular hospitals across Japan. They revealed that the 90 days mortality was 29% , and some specific clinical findings such as older age, non-sinus rhythm on admission, left ventricular ejection fraction <40%, and ventricular arrhythmia on the first day, and severe histological damage of myocardium were all associated with worse prognosis.

"A comprehensive assessment of both clinical and pathologic findings may help the prediction of outcome in patients with FM. Our results showed that about half of the patients with clinically diagnosed FM did not undergo endomyocardial biopsy, and increasing the implementation of biopsy may improve the management of FM." – Dr. Koshiro Kanaoka.

Next steps for this research are to clarify the effective treatment and the immunological mechanism of inflammation in patients with FM.

The research has been published in Circulation, the official journal of the American Heart Association, as "Features and Outcomes of Histologically Proven Myocarditis with Fulminant Presentation" (DOI: 10.1161/CIRCULATIONAHA.121.058869).

This research was supported by Japan Agency for Medical Research and Development grant 21ek0109528 and Japan Society for the Promotion of Science KAKENHI grant 20K08453.