Congestive heart failure is the most frequent cause of hospitalization among people 65 or older but is difficult to diagnose. Treatment delays increase the chances of heart damage or complications and the costs of care.
Already, doctors in many emergency rooms test for high levels of the peptide in patients with severe shortness of breath to determine whether they have congestive heart failure, in which the heart stops pumping effectively.
The substance, called B-type natriuretic peptide, could become the latest in a growing array of "biomarkers," or proteins whose levels in the blood can be used to diagnose or predict heart trouble .
One of the studies, conducted found that measuring the peptide's levels in ER patients with shortness of breath helped doctors more quickly decide whether patients had heart failure. It was also found to reduce treatment costs and hospital stay. Doctors believe a gradually failing heart tries to protect itself by secreting more and more of the peptide, which dilates blood vessels and lowers blood pressure.
A Swiss study included 452 patients who came to the hospital's ER in 2001 and 2002 with shortness of breath. To determine the cause -- congestive heart failure, a respiratory disease or something else -- all got physicals, standard blood tests, a chest X-ray and an electrocardiogram, or EKG. Half also got the peptide test. The researchers said the additional test enabled them to start the correct treatment faster. That reduced how many patients were hospitalized, from 85 percent to 75 percent.
The U.S. study found that patients with the highest levels of the peptide were about 60 percent more likely to die in five years, and twice as likely to suffer a stroke or atrial fibrillation, in which the heart's upper chambers flutter ineffectively.
However researchers conclude that larger studies are needed to see if the peptide's level can help predict heart attacks and the peptide's predictive value needs to be tested against that of other known biomarkers, such as C-reactive protein.