Antibiotics Aid Heart Patients

Aug. 19, 2002 -- Giving antibiotics for even a short time after a heart attack or chest pain may keep heart patients from coming back to the hospital for up to a year.

A new study adds more evidence to the theory that infection and inflammation play important roles in the development of heart disease. And antibiotics may be valuable weapons in countering that risk.

In the largest study of its kind to date, researchers found heart patients who took antibiotics had a much lower risk of returning to the hospital due to a heart attack or severe chest pain compared with those who didn't take the infection fighters.

The study involved 325 men and women who had been admitted to the hospital for a heart attack or chest pain. Within 48 hours of admission, the patients were given either an antibiotic (amoxicillin or Zithromax) or a placebo for one week.

A year later, those who received an antibiotic were 36% less likely to be rehospitalized for a heart attack or chest pain than those who took a placebo.

"It is an interesting proposal that antibiotics can affect a condition that has always been regarded as noninfectious," says study author Michael A. Mendall, MD, of the Mayday Hospital in Croydon, England, in a news release.

The question, Mendall says, is whether the antibiotics are working by fighting infection or inflammation in these patients.

Recent studies have suggested that substances in the body that indicate inflammation, such as C-reactive protein, fibrinogen, and white blood cells, are effective markers of heart disease risk. In addition, research has shown that infection with two common bacteria, Helicobacter pylori (H. pylori) and Chlamydia pneumoniae, are associated with heart disease.

But in this study, the researchers found treatment with the antibiotics produced heart benefits regardless of whether the person was infected with either of the bacterium.

"This implies that these antibiotics are not working against these organisms," says Mendall. The antibiotics may be acting against other organisms or may have their own anti-inflammatory properties.

Researchers say more research is needed to determine what is responsible for the lasting beneficial effects of short-term antibiotic treatment.

Their study appears in today's rapid access issue of Circulation: Journal of the American Heart Association.