A heart disease treatment that many doctors consider fringe medicine has shown some promise in a new U.S. study.

Chelation therapy is normally used to treat lead poisoning.

But in a study of 1700 heart attack survivors, those given chelation suffered fewer heart problems in later years than the group that received placebos.

The problem with the study, though, is  that so many participants quit that it may have skewed the results.

The research was discussed Sunday at a heart conference in California.