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Since he had a heart attack five years ago, Gary Reed has often felt dizzy and short of breath.

He has felt much better, however, since doctors placed an elastic mesh-metal support device around the lower part of his heart.

The device "has really turned me around," said Mr. Reed, 53, of Monroeville, who had it surgically installed in February at Allegheny General Hospital. He said he has been less tired and more able to work around the house.

Researchers at the hospital recently took part in a small study suggesting that the metallic alloy device, known as the HeartNet Ventricular Support System, may counteract harmful changes to the heart that can occur in some patients with heart failure. They are reporting the results this week at an annual meeting of the American College of Cardiology in New Orleans.

Allegheny General researchers also are participating in a much larger study to test the device's effectiveness. Like the earlier study, it focuses on patients with certain types of dilated cardiomyopathy, a condition in which the heart becomes weakened and enlarged and cannot pump efficiently.

There are many causes of dilated cardiomyopathy, including nutritional deficiencies, viral infections, alcoholism and coronary artery disease. The condition accounts for thousands of deaths each year and tens of thousands of hospitalizations.

The larger study, known as the PEERLESS HF trial, is sponsored by Paracor Medical Inc., which developed the device. Researchers at Allegheny General and at centers in other states plan to recruit about 270 patients into the study by mid-2009.

The study focuses on patients with heart problems not related to a lack of blood flow to the heart, such as viruses or hypertension. But patients with problems related to blocked arteries also may be considered if they have not had bypass surgery or the blockages are not significant, said Dr. Srinivas Murali, who is directing the Allegheny General study along with Dr. Stephen Bailey.

Dr. Murali said local researchers hope to enroll at least 10 patients into the study in the next year.

Researchers emphasized that the benefits of the device are yet to be established.

Still, it "has the potential to benefit a lot of people, especially those who may be too ill to be considered for other options such as heart transplantation," said Dr. Murali, who is medical director of the hospital's Gerald McGinnis Cardiovascular Institute.

The idea of enveloping the heart with a supportive device is not new, he noted.

One advantage of the current device, he said, is that it conforms to the shape of the heart without being too tight. It also can be placed around the heart through a minimally invasive surgical procedure.

Patients with dilated cardiomyopathy often are treated with medications such as ACE inhibitors or beta blockers, but those treatments may become less effective over time, Dr. Murali said.

"That's where a device like this can be extremely useful," he said.

He said the device may reduce stress on the wall of the heart that may trigger molecular or cellular signals that cause the heart to enlarge.

The effect is rather like placing an injured arm in a sling to heal, said Dr. Robert Biederman, director of cardiovascular MRI at Allegheny General. He was principal investigator at the hospital for the smaller study, which evaluated data from eight patients in Europe.

In that study, he and others at Allegheny General concluded that the device improved the ability of the heart's ventricles to work together.

When those pumping chambers are not coordinating well, patients tend to have worse outcomes, Dr. Murali said.

Other researchers in Europe found that the device appeared to increase the pumping ability of the left ventricle and reduced the size of both ventricles, Dr. Biederman said.

He said the research builds upon studies in animals by Allegheny General investigators that used a similar heart support device.