The technology to quickly and non-invasively predict someone's risk of sudden cardiac death has come to Wyoming.

In October, Dr. Curtis Li's cardiology practice in Casper purchased a machine that measures a person's risk of having irregular heart beats that cause cardiac arrest, which is almost always deadly.

Cardiac arrest is the sudden, abrupt loss of heart function.

"You've heard of basketball players dropping dead on the court," said Stephanie Keeney, a physician assistant at Li's office. "That's sudden cardiac death."

About 450,000 people die from sudden cardiac arrest in this country every year, Li said. This is almost a high as the number of people who die from heart attacks.

It is important to distinguish between a heart attack and cardiac arrest, said Lahn Fendelander, director of clinical affairs at Cambridge Heart, the company that makes the machine. A heart attack is "a plumbing problem" and cardiac arrest is "an electricity problem."

By predicting someone's risk of cardiac arrest, Li and his staff can take steps to try to stop the event from occurring and educate people on what to do if it does happen.

"It's the electrical instability of the heart," Li said. "People almost always die unless you can shock them immediately. If we can predict who is prone, hopefully we can save lives."

Before the test, a T-Wave Alternans test, the only way to determine someone's risk was through an electrophysiologic study - an invasive procedure in which catheters, or small tubes, are placed in the heart. The invasiveness, cost and potential risk associated with the procedure has limited its clinical adoption.

Li said the new test will allow more people to get tested.

The T-Wave Alternans test is done on only patients who exhibit some factor that heightens their chances of cardiac arrest, Keeney said.

These factors include a family history of arrhythmia, heart palpitations, the thickening of heart muscles, a history of heart disease or heart valve problems.

Li said a person who has a heart attack has a 10 percent chance of going into cardiac arrest within the first year.

Keeney, who administers the test, said it is a simple test that takes anywhere from five to 30 minutes. First, she places 13 special conductor pads on the patient's chest.

Then, the patient begins walking on a treadmill at a normal pace as the incline of the treadmill increases. The patient gets his heart rate up to 100 to 110 beats per minute and keeps it there for two and a half minutes. The incline increases again until the patient's heart rate reaches about 120 and he keeps it there for a minute and a half.

While the patient is on the treadmill, the machine measures the electrical activity of the heart, Li said. It looks at the heart on a very detailed level. It checks for any dangerous arrhythmia.

Li said it is basically an advanced EKG, or electrocardiogram.

Since October, Keeney said they have tested about 20 to 25 patients. Four of them are currently undergoing more evaluation because of their positive results.

If someone tests positive for risk of sudden cardiac arrest, Li said they should be evaluated for an implantable defibrillator, a device implanted in the chest that recognizes when a heart goes into dangerous arrhythmia and corrects them with a shock.

"It's the most sure way of preventing sudden cardiac arrest," Li said about the device.

Li said medications and surgery are not fail-proof ways of preventing cardiac arrest.

If the test is negative, the chances a person will go into cardiac arrest are slim.

A positive T-Wave test does not necessarily mean a person will receive an implantable defibrillator, Fendelander said. She said there needs to be other risks and other tests done.

"It really depends on the physician and the patient whether a device is implanted," she said.

The technology for the test was originally discovered in the mid-1980s, but the test didn't become available as a marketable product until about 10 years ago, she said.

She said this is the first such machine in Wyoming and there are about 800 others across the country. She said Cambridge Heart is the only company that manufacturers the test where it is reimbursable.

Medicare and most commercial insurance policies cover the test, Keeney said.

"Predicting it is half the battle," Keeney said. "It allows a person to go fishing or hunting in the wilderness without worrying. People can do what they want."

Contact health reporter Allison Rupp at (307) 266-0534 or

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