Simple exercise test may help detect mortality risk in heart failure patients

A simple exercise test may enable doctors predict mortality risk in patients with heart failure, according to a study of 147 patients conducted at Wake Forest University Baptist Medical Center.

Washington, May 31 : A simple exercise test may enable doctors predict mortality risk in patients with heart failure, according to a study of 147 patients conducted at Wake Forest University Baptist Medical Center.

Heart failure is the inability of the heart to pump enough blood to keep up with the body's demands, the primary symptom of which is shortness of breath.

"This may allow doctors to better assess patient risk, and could help them determine the most appropriate plan of care based on the prognosis of the patient," said senior researcher Dr. Dalane Kitzman, Professor of Cardiology, whose study has been published in the Journal of Cardiac Failure.

Lead author Dr. Brian Moore says that previous studies have already shown that the test can effectively predict future hospitalisations in patients with systolic heart failure, a type in which the left chamber of the heart is too weakened to pump blood efficiently.

He says that the present study was taken up with a view to determine if it was also appropriate for patients with diastolic heart failure, a more recently recognised form in which the heart muscle is stiff and cannot take in enough blood with each beat.

The researchers claim that theirs is the first study to compare the pulmonary test in three groups-older adults with diastolic heart failure, older adults with systolic heart failure, and healthy volunteers of the same age. The mean age of participants was 70.

"It is important for researchers not only to focus on potential treatments for diastolic heart failure, but to also develop the best method to assess the severity of their condition," said lead author Dr. Brian Moore.

During the study, the researchers measured pulmonary efficiency by analysing oxygen consumption and carbon dioxide expiration during an exercise session on a stationary bicycle.

Previous research has shown that a test score of 34 is a threshold for increased risk of death. In the current study, patients with systolic heart failure had a mean score of 37, which suggests an increased risk of mortality. Patients with diastolic heart failure had a mean score of 34, suggesting lower risk. The group of healthy older adults had a mean score of 32.

About 45 per cent of study participants with diastolic heart failure were found to have a score greater than 34, while 59 per cent of patients with systolic heart failure had a score that high.

The new results suggest that the exercise test can potentially predict mortality in individual patients.

"The study highlights an important physiologic principal of exercise intolerance and identifies a novel marker to assign risk," said Dr. Vinay Thohan, Director of the Heart Failure Service at Wake Forest Baptist.

"This measure has been validated in patients with systolic heart failure and this form of testing is routinely performed for all patients who undergo evaluation for heart transplantation at our medical center. Now, we may be able to use this test for patients with diastolic heart failure as well," he added.

The researchers are now planning to conduct further studies to examine whether treatments for heart failure can modify the results and reduce the risk of mortality.

ANI