"No-Stress” Test Brings Relief to Heart Failure Patients

The system comprises five main components and it can be used to conduct three different tests: a low-intensity, graded protocol exercise test; a standard, incremental protocol exercise test; and a steady state test. With proper training, the tests can be performed by any clinic employee. A unique feature of the system is the automatic, real-time calibration feature that eliminates the need for separate, time consuming, and technically complicated manual calibration.

Patient data and acquired test results are stored in a comprehensive database that can be retrieved and reviewed at any time. The Shape-HF system requires that the patient step up and down a 6-inch raised platform or walk a slow, steady, 1.6 km/h on a treadmill, an exertion well within the capacity of most heart failure patients. During the test, the patient breathes into a disposable tube interface while exercising at a normal daily activity level. The breaths pass into the Shape-HF data analyzer, which measures oxygen and carbon dioxide concentrations of both inhaled and exhaled air, as well as measuring airflow.

The data analyzer also has a built-in pulse oximeter, which uses either a finger or an ear probe to measure the patient's heart rate and blood oxygen saturation. These measurements provide the basis for all calculations made by the system, which the physician sees on-screen in real time; an easy-to-understand report helps referring physicians implement targeted treatments for their cardiac patients based on information from the test. The Shape-HF Cardiopulmonary Testing system is a product of Shape Medical Systems (St. Paul, MN, USA).

"The Shape-HF test is a level of exercise that is consistent with normal daily activity in this patient population. Patients I have worked with in the clinic call it a ‘cake walk' because it is quite an easy test for them to do,” said Dean MacCarter, M.S, Ph.D., vice president of clinical affairs at Shape Medical Systems.

A cardiac stress test reflects the arterial blood flow to the heart during physical exercise. When compared to blood flow during rest, the test imitates imbalances of blood flow to the heart's left ventricular muscle tissue. It has become increasingly clear that stress testing recognizes most people at risk for heart attacks too late, usually only after the disease and symptoms of the disease have developed. By the time, a majority of people would already have at least medium stenosis of coronary vessels with development of atheroma, or have already had heart attacks or died.

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