Heart attacks may be linked to oral bacteria, new study finds

Heart attacks may be linked to oral bacteria, study suggests

Heart attacks may be more closely linked to oral health than previously thought. A new study published in the Journal of the American Heart Association has found that bacteria commonly found in the mouth and throat may trigger a heart attack by infiltrating coronary plaques and causing inflammation.

According to the World Health Organization (WHO), about 19.8 million people worldwide died from heart disease in 2022, with nearly 85% of these deaths attributed to stroke and heart attack. Heart attacks, medically called myocardial infarctions, occur when blood flow to the heart is blocked — often due to blood clots, coronary spasms, or plaque buildup on the artery walls.

Oral bacteria discovered in coronary plaques

Researchers at Tampere University in Finland analyzed coronary plaque samples from 121 individuals who had died of sudden cardiac death and from 96 patients who underwent plaque removal surgery (endarterectomy).

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They found that viridans group streptococci — a type of bacteria commonly present in the mouth, saliva, and dental plaque — were the most frequently detected microbes in the arterial samples.

Professor Pekka J. Karhunen, MD, PhD, who led the study, explained that these bacteria may not cause harm when confined to the dental biofilm. However, under certain conditions, the biofilm may activate, releasing bacteria that infiltrate arterial plaques, triggering inflammation and potentially causing a rupture that leads to a heart attack.

Why this research matters

Experts say the findings add to growing evidence of the oral-systemic connection — the idea that oral health can directly influence cardiovascular health.

Dr. Sergiu Darabant, a cardiologist at Miami Cardiac & Vascular Institute, noted that inflammation has long been suspected as a key driver of plaque rupture. “This study adds another piece to the puzzle — showing how bacteria from the mouth might play a hidden role in driving coronary inflammation,” he said.

What this means for patients

Medical experts emphasize that strep viridans is normally a benign bacterium that helps maintain a healthy oral ecosystem. Problems arise when oral infections are left untreated, allowing bacteria to enter the bloodstream and contribute to systemic inflammation.

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To reduce risks, cardiologists and infectious disease specialists recommend:

• Maintaining optimal oral hygiene through regular brushing, flossing, and professional cleanings
• Seeking prompt treatment for dental infections to avoid bacteria entering the bloodstream
• Keeping vaccinations up to date, including influenza, COVID-19, and pneumococcal vaccines, to lower infection-related cardiovascular risks

The bigger picture

This study highlights the importance of integrating dental care into overall cardiovascular prevention strategies. Early detection and treatment of oral infections, combined with lifestyle changes and medication for cholesterol, blood pressure, and diabetes, may significantly reduce the risk of heart attacks.

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