Posted Online: April 22, 2013, 12:37 pm

New blood test helps doctors identify heart attacks quicker

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Bushra Tayh, btayh@qconline.com

DEAR DOCTOR K: I've heard there's a new test that can help doctors diagnose a heart attack more quickly. Can you tell me about it?
DEAR READER: A heart attack instantly is recognizable on TV and in the movies: The actor breaks into a sweat and clutches his heart. But in real life, a heart attack isn't always so easy to identify.
There are many different conditions that can cause pain in the chest and sudden sweating. A heart attack is just one of many possibilities, though one of the most serious. The main tests doctors use to diagnose heart attacks are blood tests and heart tests (the first of which is usually an electrocardiogram). The results of the EKG are immediate, but the blood tests can take hours to give results.
Over the years, different types of blood tests have been used to diagnose heart attacks. In recent years, the most widely used tests measure the blood levels of different types of a chemical called troponin. A heart attack kills some heart muscle cells. When they die, they spill the troponin that is inside them into the blood.
Within the first few hours of a heart attack, though, both the troponin level and the EKG can be normal. People can spend 12 to 16 hours waiting in an emergency room. That's a long time to sit there wondering if you might have a condition that could kill you, or if it's just a bad case of acid reflux that's causing the pain.
A new blood test may help speed the diagnosis. This is important because the sooner a heart attack is diagnosed, the sooner treatment can begin. And the sooner treatment begins, the more heart muscle can be saved.
The new test you're probably asking about is a new high-sensitivity cardiac troponin T test that can detect smaller amounts of troponin in the bloodstream. This could let doctors identify small heart attacks that would otherwise go undiagnosed, or identify heart attacks earlier.
We know it's important for doctors to quickly diagnose a heart attack. But it's even more important for people with chest pain or other signs of a heart attack to get to the hospital as soon as possible.
Call 911 right away if you have:
-- uncomfortable pressure, squeezing, fullness, burning, tightness or pain in the center of your chest;
-- pain, numbness, pinching, prickling or other uncomfortable sensations in one or both arms, your back, neck, jaw or stomach;
-- shortness of breath;
-- sudden nausea or vomiting;
-- lightheadedness or dizziness;
-- unusual fatigue, especially if accompanied by a great deal of sweating;
-- sudden heaviness, weakness or aching in one or both arms.
These symptoms don't mean you definitely are having a heart attack, but they do mean the risk you're having a heart attack is high enough that you need to get it checked out, and fast.
Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.