New test may speed detection of heart attacks

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A heart attack (more formally known as myocardial infarction) isn't always an instantly recognizable event. Severe chest pain often has nothing to do with the heart or blood vessels. Some heart attacks are so small they pass almost unnoticed, written off as indigestion or the flu. Others are major catastrophes, causing death or long-lasting disability.

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. The sooner treatment begins, the more heart muscle can be saved.

Fifty years ago, doctors had to rely on a person's symptoms and sometimes hard-to-interpret changes on an electrocardiogram to determine if a heart attack was under way. Today, blood tests are available that can detect the chemical signature of dying heart cells. The blood test preferred today is called troponin. Troponin is a protein complex found almost exclusively in heart and skeletal muscle cells. Its sudden release into the bloodstream signals damage to the heart muscle. Combining troponin results with characteristic changes on the electrocardiogram and symptoms is currently the gold standard for identifying myocardial infarction.

Within the first few hours of a heart attack, though, both the troponin level and the electrocardiogram can be normal. That means people with results in the gray zone are observed and monitored for 12 to 16 hours with more troponin tests and electrocardiograms.

The new high-sensitivity cardiac troponin T test 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—and begin treatment earlier. Results of a study of the test, published online this week in the Archives of Internal Medicine, showed that it helped emergency room doctors rule out heart attack in just a couple hours.

Skip the home diagnosis

While it is important for doctors to quickly tell the difference between a heart attack and something else, like pancreatitis or a panic attack, it's even more important for people with chest pain to get to the hospital as soon as possible, and not try to make a diagnosis themselves. Far too many people delay calling 911 or going to the hospital, and by the time they do a substantial section of heart muscle has died.

When it comes to chest pain, it's better to be safe than sorry. (For more information on chest pain and heart attacks, I recommend that you read this article from the Harvard Heart Letter.) Keep in mind that chest pain is only one of the possible signs of an impending heart attack. Call 911 or your local emergency number right away if you have:

• Uncomfortable pressure, squeezing, fullness, burning, tightness or pain in the center of the chest
• Pain, numbness, pinching, prickling or other uncomfortable sensations in one or both arms, the back, neck, jaw or stomach
• Shortness of breath
• Sudden nausea or vomiting
• Lightheadedness or dizziness
• Unusual fatigue, especially if accompanied with a great deal of sweating
• Sudden heaviness, weakness or aching in one or both arms