Since 2005, the mortality from myocarditis has decreased, although it remains a difficult disease to treat and diagnose, according to a recent review.

Lead researcher Stephane Heymans, MD, of Maastricht University Medical Centre in the Netherlands, and colleagues published their findings in the Journal of the American College of Cardiology on Nov. 29.

The researchers defined myocarditis as “acute or chronic inflammatory responses of the heart to environmental or endogenous triggers, most commonly viruses, and less frequently bacteria, fungi, and parasites.”

In 2013, approximately 1.5 million people in the world had myocarditis, which translates to an incidence of 22 per 100,000 people, according to the researchers. By 2015, approximately 354,000 people died from myocarditis for a death rate of 4.8 per 100,000 people.

A news release from the Mayo Clinic mentioned that myocarditis is responsible for up to 45 percent of heart transplants in the U.S. and accounts for approximately 5 percent of sudden cardiovascular infant deaths and up to 20 percent of sudden cardiovascular death in adolescents.

Leslie T. Cooper Jr., MD, a study co-author from the Mayo Clinic, said in the news release that the most common cause of myocarditis is an infection that can damage the heart even in healthy people.

The researchers noted that patients often have a viral syndrome before the presenting with acute myocarditis and typically have concurrent chest pain or dyspnea. They recommended that patients with suspected acute myocarditis undergo an endomyocardial biopsy or a cardiac MRI depending on their symptoms.

Approximately 60 to 70 percent of people with acute cardiomyopathy from myocarditis improve, although Cooper said that 10 to 15 percent develop an irreversible chronic disease and are treated with heart failure treatments. However, 20 percent of those patients die within a decade due to heart failure, according to Cooper.

“I see patients everyday with this disorder,” Cooper said in a news release. “We are on the cusp of trying more tailored treatment, and it can’t come soon enough.”

The researchers suggested that patients follow current guidelines and scientific statements. For instance, patients with myocarditis presenting as heart failure with reduced systolic function, should have gradual titration of ACE inhibitors, ARBs and beta-blockers.

“Multicenter trials examining pathway- and pathogen-specific treatments are underway presently, using immunohistochemical and molecular analysis as part of the enrollment criteria,” the researchers wrote. “Peripheral T-cell, DC, monocyte, and NK-cell activation patterns may differ in myocarditis compared with noninflammatory [dilated cardiomyopathy], or between different viruses and purely autoimmune processes. Multiple groups are searching for peripheral blood immune markers in proteins, and in coding or noncoding RNAs for diagnosis and to guide emerging therapies, such as RNA interference. The path toward personalized treatment in acute myocarditis requires deep clinical and immunological phenotyping. More specific therapeutic approaches proposed or under clinical investigation include individualized antiviral strategies, miRNA-based gene-silencing strategies, cytokine targeting, and pharmacological modulation to alter tissue monocytic precursors of cardiac fibrosis.”