New insights into viral-related myocarditis

Researchers at the Fralin Biomedical Research Institute have provided a novel understanding of sometimes fatal viral infections that affect the heart. Up to 42 percent of sudden cardiac deaths in young adults are attributed to myocarditis, of which viral infection is the leading cause, meaning that these insights are crucial.

The focus of previous research has been on myocarditis, which is often triggered by the body’s immune response to a viral infection. However, in the new study it has been shown that the virus itself creates potentially dangerous conditions in the heart before inflammation sets in. 

Dr James Smyth, associate professor, explained: “From a clinical perspective, our understanding of viral infection of the heart has focused on inflammation, causing problems with the rate or rhythm of the heartbeat…But we have found an acute stage when the virus first infects the heart and before the body’s immune response causes inflammation. So even before the tissue is inflamed, the heart is being set up for arrhythmia.”

The team concentrated on adenovirus, a common virus in cardiac infection and myocarditis. They used Mouse Adenovirus Type-3 to replicate the human infection process, and saw that early in the infection, the virus disrupts critical components of the heart’s communication and electrical systems. The study’s first author, virologist Dr Rachel Padget, said even before symptoms appear, the adenoviral infection creates conditions that disrupt the heart’s gap junctions and ion channels.

When the gap junctions and ion channels are disrupted, the heart could develop arrhythmias, resulting in sudden cardiac problems, particularly in people with active infections. The researchers hope to reduce the risk of cardiac issues in patients with viral illnesses by targeting specific heart changes induced by viral infections at the molecular level.

“Individuals who have acute infections can look normal by MRI and echocardiography, but when we delved into the molecular level, we saw that something very dangerous could occur,” Dr Smyth stated.

He continued: “In terms of diagnostics, we can now work with our colleagues here to start looking ways to analyse blood for a biomarker of the more serious problem. People get cardiac infections all the time and they recover. But can we identify what’s different about individuals that are at a higher risk to have the arrhythmia, possibly through a simple blood test in the doctor’s office.”

This study was published in Circulation Research.