WEDNESDAY, June 15, 2005 (HealthDayNews) -- Helicobacter pylori, a bacteria that lives in the stomach and small intestine and causes ulcers, may also be linked to a dangerous, irregular heart rhythm known as atrial fibrillation (AF), a new Italian study suggests.
"This is the first observation ever made on H. pylori infection as possible trigger of AF," said lead researcher Dr. Annibale Montenero, chairman of the Cardiology Department and Arrhythmia Centre at Multimedica General Hospital, in Milan. He pointed out that over 90 percent of patients with AF also suffer from the stomach disorder gastroesophageal reflux.
Montenero and colleagues base their findings on a study of 59 patients with persistent atrial fibrillation. None of these patients had structural heart disease, according to the report in the July issue of Heart.
The research team gave the patients a series of tests, including a heart tracing and measurements of blood levels of C-reactive protein, an indicator of arterial inflammation. Patients were also tested for H. pylori. Montenero's group then compared the test results of the AF patients with 45 healthy people who took the same tests.
They found that patients with AF were about 20 times more likely to test positive for H. pylori compared with healthy volunteers. In addition, AF patients had C-reactive protein levels about fivefold higher than healthy volunteers.
H. pylori has properties that allow it to escape detection by the immune system, the researchers note. Chronic gastritis caused by H. pylori may predispose people to AF, they speculate.
Montenero believes that getting rid of the bacteria may help treat AF. "Curing the gastric disorder may relieve the episodes of AF, or at least reduce them so much as to be acceptable and treatable," he said.
Based on the findings, he advises that physicians check their AF patients for H. pylori and eliminate it whenever it is found. The next step would be to recheck the patient again for AF. "Sometime it happens that AF disappears or it [becomes] much better controlled by drugs that were previously ineffective," he said.
Atrial fibrillation is a heart disorder affecting about 2.2 million Americans, according to the American Heart Association. In atrial fibrillation, the heart's two upper chambers (the atria) quiver instead of beating effectively. Blood isn't pumped completely out of them, so it may pool and clot.
If a blood clot in the atria leaves the heart and becomes lodged in an artery in the brain, a stroke results. About 15 percent of strokes occur in people with atrial fibrillation. The likelihood of developing atrial fibrillation increases with age. Three percent to 5 percent of people over 65 have atrial fibrillation.
One expert believes the findings are interesting but inconclusive.
"This is all hypothesis," said Hrayr S. Karagueuzian, a senior research scientist in the Division of Cardiology at Cedars-Sinai Medical Center and a professor of medicine in-residence at the David Geffen School of Medicine at the University of California, Los Angeles.
"There is no solid data," he said. "They found an association between H. pylori and AF, but you know associations can be misleading."
Moreover, Karagueuzian doesn't believe the relationship can be causal. "It would have been nice to know in which patients with similar gastric distress no AF emerges," he said. "In the absence of these data, the proposed hypothesis remains highly speculative."
The American Heart Association can tell you more about atrial fibrillation.