New Blood Test Detects Or Rules Out A Heart Attack In As Little As An Hour
When you walk into the hospital with chest pain, doctors will conduct a physical exam, get your medical history and do an echocardiogram or EKG to measure electrical activity in the heart.
And then there’s the blood test to diagnose or rule out a heart attack.
“One of the ways we detect a heart attack is we look for things that should live inside a heart muscle cell that get released when the heart muscle cell dies. One of those is a protein called cardiac troponin,” said Dr. Sandeep Das, director of acute coronary care at Parkland Hospital System and associate professor of internal medicine at UT Southwestern Medical Center.
“Specifically, you’d look for a rise and then a fall of the detectable enzyme troponin in the blood to help diagnose a heart attack,” he said.
Das says results take at least six to eight hours. Parkland and UT Southwestern Medical Center are among the first hospitals in the country to embrace a new FDA-approved blood test that can diagnose or rule out heart attacks faster.
“It can detect a rise [in troponin] earlier,” Das said. “It’s also more precise. Some people with conditions like a thickened heart muscle can have elevations of troponin, but flat. What this test would allow you to do is very precisely say it’s not changing.”
How a blood test detect heart attacks: One of the definitions of a heart attack is death of some your heart muscle. And one of the ways we detect a heart attack is we look for things that should live inside a heart muscle cell that get released when the heart muscle cell dies. So, one of those is a protein called "cardiac troponin." That normally lives inside all the cardiac muscle cells. When those muscle cells die like in a heart attack, cells themselves break open and the things that were inside them get released out. If we can detect quantities of that in the blood, then that’s abnormal. Specifically, you’d look for a rise and then a fall of the detectable enzyme troponin in the blood to help diagnose a heart attack.
How the new blood test speeds up the diagnosis: The traditional algorithm that we use today takes at least six to eight hours to get an answer. With the new higher sensitivity assay, we can definitively rule out a heart attack in about 50 percent of patients by one hour.
What makes it faster? It’s more sensitive and more precise. It can detect a rise [in troponin] earlier. It’s also more precise. Some people with conditions like a thickened heart muscle can have elevations of troponin, but flat. What this test would allow you to do is very precisely say it’s not changing.
FDA approval of the test years after Europe: I think they decided to be heavily on the side of safety, at least historically. In Europe, where this test has been used for about five or six years, they don’t universally test everybody that walks in the door with chest pain. They’re very selective. If you or I came into the hospital with bad indigestion, we’d probably get a blood test to make sure we weren’t having a heart attack, and that’s something that would probably less likely in Europe.
Signs of heart attack
Some heart attacks are sudden and intense. But most start slowly, with mild pain or discomfort. Pay attention to your body and call 911 if you experience:
- Chest discomfort. Most heart attacks involve discomfort in the center of the chest that lasts more than a few minutes – or it may go away and then return. It can feel like uncomfortable pressure, squeezing, fullness or pain.
- Discomfort in other areas of the upper body. Symptoms can include pain or discomfort in one or both arms, the back, neck, jaw or stomach.
- Shortness of breath. This can occur with or without chest discomfort.
- Other signs. Other possible signs include breaking out in a cold sweat, nausea or lightheadedness.