A common bacterial infection implicated in the majority of stomach ulcers may also harm the heart, according to a new study that links H. pylori to the development of an irregular heartbeat.

Irregular heart rhythm, also known as atrial fibrillation, causes the heart to beat inefficiently. According to the American Heart Association, most people with the abnormal rhythm have only unpleasant symptoms and no harm. However, it can result in pooling of blood in the heart chambers, increasing the risk of clots that cause stroke. If the irregular heartbeats continue, heart failure can occur.

In the study, researchers found that people with atrial fibrillation were 20 times more likely to test positive forH. pylori, the bacteria that can cause stomach ulcers, than people without the condition.

Researchers say it's the first study to link atrial fibrillation to H. pylori.

Read WebMD's "Medical Reference: Atrial Fibrillation Basics"

H. pylori Linked to Atrial Fibrillation

Italian researchers say the idea for the study came after they discovered that many of the patients treated at their cardiology clinic for atrial fibrillation also had stomach problems.

They tested 59 people with persistent atrial fibrillation for H. pylori and C-reactive protein, an indicator of inflammation that is associated with heart disease and other health problems. They compared the results with those of 45 healthy volunteers.

The results, which appear in the current issue of the journal Heart, showed that H. pylori was nearly 20 times more common in people with atrial fibrillation than in the comparison group. In addition, C-reactive protein levels were about five times higher among those with atrial fibrillation.

Although more studies are needed to confirm the link between H. pylori and atrial fibrillation, researchers say the results suggest that chronic infection with this bacterium may predispose people to the development of irregular heartbeat.

Read WebMD's "Hope for the Heart: Treatment Advance"

By Jennifer Warner, reviewed by Brunilda Nazario, MD

SOURCES: Montenero, A. Heart, June 16, 2005; vol 91: pp 960-961. News release, BMJ Specialists Journals. National Digestive Disease Information Clearinghouse. American Heart Association.