Cardiopulmonary Exercise Testing Provides Better Data For Evaluation

Main Category: Cardiovascular / Cardiology
Also Included In: Heart Disease;  Respiratory / Asthma
Article Date: 29 Jun 2010 - 10:00 PST

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Cardiopulmonary exercise testing (CPX), widely used by lung specialists, helps manage heart disease, particularly in those with chronic heart failure, according to a new American Heart Association scientific statement.

View the Scientific Statement

CPX is a non-invasive and objective method to evaluate heart and lung function. It provides physicians data on gas exchanges in the lungs at rest and during exercise and yields breath-by-breath measures of oxygen uptake. Combining these findings with data traditionally obtained by cardiologists from treadmill or bicycle tests - such as heart rate, blood pressure and electrocardiogram changes - provides information that can yield a more comprehensive evaluation, said Gary J. Balady, M.D., professor of medicine at Boston University and chair of the expert panel that wrote the statement.

"Cardiopulmonary testing is generally readily available, and it has great utility in clinical practice for people with heart and lung disease," he said. "Your peak fitness level is measured by oxygen uptake, and fitness is the most important prognostic variable of any data we can get from an exercise tolerance test."

Although CPX has long been used to assess athletic performance and in research, its burgeoning value in the clinical setting prompted the American Heart Association to convene a group of experts to write its first comprehensive cardiopulmonary exercise testing guide for heart specialists. The new statement, published in Circulation: Journal of the American Heart Association, is a supplement to the association's existing guidelines for exercise testing.

"There has been limited or absent training of cardiovascular specialists on the administration and interpretation of CPX, and a lack of understanding of its value," Balady said. "However, modern CPX systems allow for simple and complex analyses of these data that are easy to retrieve and store, which makes CPX available for widespread use."

The statement covers the usefulness of CPX in cardiovascular disease, selecting procedures, patient monitoring, device calibration, maintenance and quality control.

"The purpose of the statement is to acquaint clinicians with what is going on with exercise testing," said Martha Gulati, M.D., co-author of the study and assistant professor of medicine and preventive medicine at Northwestern University's Feinberg School of Medicine in Chicago. "It has really evolved, but if you ask many physicians, all they know is that it diagnoses ischemia."

Cardiac exercise stress tests, typically done using a treadmill, require physicians to estimate the patient's oxygen uptake, using regression-analysis formulas. Even then, the best estimates can be inaccurate by about 10 percent or more, particularly if handrail support is used.

CPX is especially useful in assessing heart failure patients. According to AHA/ACC guidelines, peak oxygen uptake is useful in these patients to:

- determine the severity of the disease;
- help determine whether heart failure is causing shortness of breath, a common ailment of lung disease;
- identify candidates for heart transplantation or other advanced treatments;
- assess whether new drugs or devices are effective;
- help physicians design exercise programs.

People who suffer mild-to-moderate strokes may lose up to half their previous fitness level. Customized exercise regimes, based on CPX findings, have increased fitness by 8 percent - 23 percent in patients during stroke recovery.

Emerging uses of CPX in heart patients include:

- predicting hospitalization or death for adults with congenital heart disease;
- diagnosing ischemic heart disease;
- evaluating cardiac pacemakers, particularly pacemakers used by younger or more physically active patients, who may require optimal rate response settings.

"The nice part about cardiopulmonary testing is that it provides excellent, objective data on the functioning of an individual's heart and lung capacity," Balady said. "This guideline is geared toward individuals who take care of heart disease, but many patients with heart disease have lung disease as well."

Other co-authors are: Ross Arena, Ph.D.; Kathy Sietsema, M.D.; Jonathan Myers, Ph.D.; Lola Coke, R.N., Ph.D.; Gerald F. Fletcher, M.D.; Daniel Forman, M.D.; Barry Franklin, Ph.D.; Marco Gauzzi, M.D., Ph.D.; Steven J. Keteyian, Ph.D.; Carl J. Lavie, M.D.; Richard Macko, M.D.; Donna Mancini, M.D.; and Richard V. Milani, M.D.

Source:
American Heart Association
American Stroke Association

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