A patient’s heart efficiency is usually assessed using a stress test that requires near peak performance.
"Heart failure patients are simply unable to undergo the kind of exertion a stress test requires," says Dr. Abraham Kocheril, UIC professor of medicine and director of clinical electrophysiology.
But with the Shape-HF Cardiopulmonary Testing System, the patient need only step up and down a 6-inch raised platform or walk a slow, steady, 1 mph on the treadmill — exertion well within the capacity of most heart failure patients.
The patient breathes into a tube while exercising at a normal daily activity level. The breath passes through a small box where it is analyzed for the blood gases, and a computer shows the physician the results in real time.
In heart failure, a patient’s heart is unable to pump effectively and cannot meet the body’s need for blood and oxygen. More than 5.5 million Americans have heart failure, according to the American Heart Association, and 670,000 new cases are diagnosed each year.
Patients with heart failure tire easily, suffer from shortness of breath and are often unable to work. Implanted electronic medical devices that monitor heart rhythm and stimulate the heart when arrhythmias occur can be life-saving for many and dramatically improve their quality of life, making breathing easier and keeping them out of the hospital.
But 30 percent of patients do not respond to these implanted defibrillators and pacemakers, Kocheril said, and optimizing the settings of the devices has been a process of trial and error.
Queen Page, 66, of Chicago, came to UIC for the test using a scooter and a cane. After four heart attacks, she had had a cardiac re-synchronization therapy defibrillatorimplanted in 2006. Although she did well at first, she was set back by a car accident and was once again suffering from weakness and fatigue.
As she began her test, even walking on the treadmill at the very slow pace of 1 mph was difficult. But as Page walked, Kocheril optimized her defibrillator by making fine adjustments using readouts of her blood gases every two minutes. "By the end of the test I felt good enough to go dancing!" Page said.
Today, Page walks to the bus stop, church, and everywhere she needs to go. No cane, no scooter. She rides her stationary bike three times a day for 15 minutes and has signed up for a step class at her local gym.
Kocheril also sees potential for the new diagnostic tool in a number of other cardiac conditions. Pulmonary arterial hypertension, for example, often presents non-specific symptoms and a combination of lung and heart problems. Current tests do not give the physician enough information to discern how to appropriately treat this mix of problems, Kocheril said.
"’Shape’ will give us potentially more objective and directly relevant information, allowing a much more targeted medical approach," he said.
Kocheril worked with Shape Medical Systems, Inc., developer of Shape-HF, to produce an easy-to-understand report that can help referring physicians implement targeted treatments for their cardiac patients based on information from the test.