Acute myocardial infarction (MI) is a common cause of death and disability in the United States and around the world. Each year, about 735,000 Americans suffer an MI — 525,000 are a first heart attack and 210,000 are a second MI. Prompt treatment depends on early diagnosis, and both are critical to patient survival.

However, a new strategy may help emergency department physicians determine more quickly whether a patient has suffered a heart attack, according to results of a recent clinical trial. The research, published in the Canadian Medical Association Journal (CMAJ), showed the new method could spot acute myocardial infarction in 3 out of 4 cases within the first hour.

Currently, clinicians order troponin tests to evaluate patients presenting with chest pain to determine whether the patient has sustained damage to the heart. While practitioners often order CK-MB, myoglobin and other biomarkers too, troponins are the preferred test for MI because they are more specific for heart injury and may remain elevated longer than other cardiac biomarkers.

Slow laboratory turnaround time for cardiac biomarkers can have a detrimental effect on patient outcome. There is consensus among clinicians that a one-hour turnaround time is optimal, yet not all results make it back within that golden hour. In fact, one 2008 study showed an average turnaround time of 122 minutes, more than double the recommended reporting time.

Researchers from Switzerland and Spain wanted to determine whether a new technique might be effective in establishing whether a patient has suffered an MI. Scientists had previously tested the measure of cardiac troponin T levels in the blood, a preferred biomarker for the diagnosis of acute MI, in a small pilot study.

The researchers enrolled 1,320 participants who had presented to the emergency department with possible acute myocardial infarction. The authors of the study then applied the high-sensitivity cardiac troponin T one-hour algorithm to blood samples taken from the participants.

Using the algorithm, the scientists determined that 786 patients, about 60 percent, did not have an MI. The researchers ruled in acute MI in 216 patients, or about 16 percent. Results were inconclusive in 318 cases, which is 24 percent of participants.

"Introducing the high-sensitivity cardiac troponin T one-hour algorithm into clinical practice would represent a profound change, and it is therefore important to determine if it works in a large patient group," said the lead author of the study, Dr. Tobias Reichlin, Division of Cardiology, University Hospital Basel, Switzerland.

More research is necessary before the new algorithm enjoys widespread use in emergency departments.