“Can you walk up a flight of stairs?” a cardiologist asks a chronic heart-failure patient in order to assess her heart and lung function. Then the doctor orders what is sometimes called a stress test, monitoring her heart while she takes a six-minute walk on a treadmill. This test can be very strenuous for some people; shortness of breath may have been the very symptom that brought them to the cardiologist’s office.
A new device, the Shape-HF Cardiopulmonary Testing System, from the St. Paul medical device company Shape Medical Systems, Inc., helps physicians determine a patient’s cardiopulmonary health in a less taxing way. The Shape-HF can quantify shortness of breath and its source, making it possible for a doctor to more precisely evaluate therapy options in an office setting. Until recently, tests providing this kind of detailed data were only available at sophisticated cardiopulmonary centers.
“What this enhances is how [doctors] assess patient functional capacity, and how they determine how sick the heart-failure patient is,” says Clarence Johnson, president and COO of Shape Medical.
The device consists of a special tube that the patient breathes into, a gas analyzer system, a computer, and software. The test is easier on patients who are short of breath, because they only have to raise their heart rate by 10 to 15 beats per minute while exercising on a treadmill or stair-step machine. The traditional test requires raising the heart rate by more than 15 beats per minute.
Breathing efficiency is important because it relates to how well the heart can circulate blood to the lungs. “In a six-minute test [using Shape-HF], we can tell you how the blood is circulating, how well the heart is working, how well the lungs are working, and how well the heart and lungs are working together,” Johnson says. “What this gives doctors is better decision-making capacity.”