New research shows bacterial infections may trigger heart attacks. Dormant biofilms in arterial plaques can awaken after stressors like viral infections, causing inflammation and rupture. Targeted treatments or vaccines may transform prevention.
For decades, heart attacks have been blamed mainly on cholesterol buildup, smoking, and poor lifestyle choices. But groundbreaking new research suggests another hidden culprit may be at work: infections.
A team of scientists from Finland and the UK has discovered that bacterial biofilms—sticky layers of microbes—can hide inside arterial plaques for years or even decades. These dormant bacterial colonies remain invisible to the immune system and untouched by antibiotics, protected by the biofilm’s gelatinous shield.
How Bacteria Trigger a Heart Attack
According to the study, the danger begins when a viral infection or other external stressor “wakes up” the dormant bacteria. Once active, the microbes trigger inflammation that can rupture the fibrous cap of cholesterol-rich plaques in the arteries. The rupture can then lead to blood clots and blockages—the classic pathway to a heart attack.
Professor Pekka Karhunen, who led the study, explains: “For years, we assumed that coronary artery disease was caused only by oxidized cholesterol. But our findings show that bacteria are not just bystanders—they’re hiding in the plaques themselves.”
Proof from Human Samples
The researchers analyzed arterial tissue samples from patients with atherosclerosis and individuals who had died from sudden cardiac death. Using advanced genetic tools, they detected DNA from several oral bacteria lodged deep inside the plaques.
They also developed antibodies to target these bacteria, which unexpectedly highlighted structured biofilms in the arteries. In cases of heart attack, the immune system’s response to these bacteria appeared to trigger the destructive inflammation that ruptures plaques.
A New Way Forward
This discovery could radically change how we think about heart disease. Instead of focusing solely on cholesterol, future prevention and treatment strategies may also target infections.
Researchers suggest that new diagnostics, antimicrobial therapies, or even vaccines could one day prevent heart attacks by eliminating the bacterial component of arterial disease.
The study, a collaboration between Tampere and Oulu Universities, the Finnish Institute for Health and Welfare, and the University of Oxford, is part of a large EU-funded cardiovascular research project. Their findings were recently published in the Journal of the American Heart Association.