While it may be easy to "see" abnormal heart-valve function on an echocardiogram, it can be harder to define the extent of the problem. And often what is "seen" on an echocardiogram does not translate into any clinical problem.

The differences among trivial, mild, and moderate valve disease can be difficult to discern, and physicians rely on several factors in these images to determine the severity of the leakage. Even expert cardiologists sometimes disagree on what is significant disease and what isn't.

To complicate matters further, even when testing the same patient, echocardiographic images obtained on one type of machine may vary significantly from those obtained on another manufacturer's machine.

The studies published to date have not allowed physicians to estimate just how great the danger of heart-valve problems may be for the many people who took these drugs. The studies reported in September 1998 present a wide range of possibilities, ranging from 0.12%-26%.

It is also possible that valve damage detected in some of these patients may not be related to the use of diet drugs at all. The studies do, however, suggest that for the vast number of patients who took these drugs --even those with abnormal echocardiograms -- the number actually affected clinically is small.

The long-term implications of the valve disease discovered in these patients also are unclear. However, the FDA recommends that anyone who has taken Adipex should see his or her doctor for a physical exam. In addition, anyone with symptoms of heart disease or a heart murmur or who is scheduled to undergo a procedure that may introduce bacteria into the bloodstream should have an echocardiogram.