In a groundbreaking discovery, scientists from Finland and the UK have found strong evidence that heart attacks—also known as myocardial infarctions—might actually be caused by an infection.
This new idea is changing how doctors and researchers think about heart disease and could lead to new ways to treat, diagnose, and even prevent it.
The study found that inside the arteries of people with heart disease, there are hidden bacterial biofilms. A biofilm is a slimy layer of bacteria that can form over time—sometimes over many years—inside the fatty plaques in the arteries.
These bacteria stay “asleep” and protected by a gel-like shield, which makes them invisible to the immune system and safe from antibiotics.
However, if a person gets a viral infection or some other trigger, the biofilm can “wake up.” The bacteria start to grow, causing the immune system to respond with inflammation. This inflammation can damage the artery walls and burst the cholesterol-filled plaque. When that happens, a blood clot can form, blocking the artery and causing a heart attack.
Professor Pekka Karhunen, who led the study, explained that until now, it was believed that heart attacks were mainly caused by bad cholesterol (LDL) building up and triggering a reaction in the body.
But now, the presence of bacteria—especially those from the mouth—has been proven in artery plaques. The researchers even found bacterial DNA inside these plaques.
To confirm their results, the scientists created an antibody that could target the specific bacteria they found. This antibody revealed biofilm structures in artery tissue. In people who had suffered heart attacks, the researchers found signs that bacteria had escaped from the biofilm and triggered the body’s immune system, leading to dangerous inflammation.
This exciting discovery could change everything. If heart attacks can be caused or worsened by bacteria, doctors might one day use antibiotics or even vaccines to prevent them. It also means that oral health might be even more important to heart health than we previously thought.
The study was carried out by teams at Tampere and Oulu Universities in Finland, the Finnish Institute for Health and Welfare, and the University of Oxford in the UK. They used tissue samples from people who had died suddenly as well as from patients with artery disease undergoing surgery.
This research is part of a larger European Union project involving scientists from 11 countries. It was also funded by the Finnish Foundation for Cardiovascular Research and the Jane and Aatos Erkko Foundation.
The full research article is titled “Viridans Streptococcal Biofilm Evades Immune Detection and Contributes to Inflammation and Rupture of Atherosclerotic Plaques” and was published in the Journal of the American Heart Association.
The study is published in the Journal of the American Heart Association.
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