Heart Attack Diagnosis

Sweating, difficulty breathing and chest pain persisting for longer than thirty minutes are possible signs of a heart attack. When these or other signs of a heart attack are present, a number of tests are available to confirm the diagnosis. The most commonly used diagnostic tools include EKG results, cardiac enzyme blood tests, and heart ultrasound.

Cardiac Enzymes and Medical Diagnosis

A heart attack causes damage to heart tissue. This damaged heart tissue releases particular cardiac enzymes into the blood. When the concentrations of these enzymes are high enough, they indicate that a heart attack has occurred. Blood tests for cardiac enzymes help make the medical diagnosis, especially when combined with EKG results.

Blood tests for the cardiac enzyme creatine phosphokinase MB (CKMB) are commonly used during a heart attack diagnosis. CKMB enzymes appear in blood test results within four to six hours after a heart attack and peak within 12 to 24 hours. After two or three days, cardiac enzymes can no longer be detected by blood tests, so these tests are only useful to detect recent heart attacks.

Other cardiac enzymes used in the medical diagnosis of a heart attack include Troponin T and Troponin I. Additionally, in 2003, the FDA approved the use of another test to assist in the diagnosis of AMI: Albumin Cobalt Binding (ACB) is a test used to help rule out a heart attack. Studies indicate that when combined with EKG and tests for the cardiac enzymes, ACB improves diagnostic accuracy in ruling out a heart attack by twenty percent.

EKG (Electrocardiogram)

An EKG is often used to help make a medical diagnosis when signs of a heart attack are present. An EKG, also abbreviated ECG, uses electrodes that are attached to the chest and detect the heart’s electrical impulses. While negative EKG results cannot rule out the possibility of an acute myocardial infarction (AMI), positive findings can be helpful by demonstrating changes in heart function and helping to locate damaged areas of the heart muscle. This information is used to determine treatment options. Since an EKG can be completed within minutes and produces results quickly, it is invaluable when an emergency diagnosis is needed.

Ultrasound and Echocardiogram

An ultrasound technique called an echocardiogram is becoming a more popular tool for medical diagnosis of heart attacks. Ultrasound waves are used to construct an image of the heart muscle. Examining the ultrasound image may reveal signs of a heart attack, including tissue damage, thrombosis, and narrowed coronary arteries. Doppler ultrasound provides additional information about blood flow through the heart and helps determine how effectively the heart is pumping.

Medical Diagnosis After a Heart Attack

The diagnostic tools described above assist in the emergency diagnosis of a heart attack. Other, more involved tests may be used to provide more detailed diagnostic information after emergency treatment, and to determine the extent of cardiac damage and arterial narrowing. Follow the link to learn more about echocardiography and other tools.


Food and Drug Administration. (2003). FDA clears new lab test to help rule out heart attack. Retrieved January 28, 2004, from www.fda.gov/bbs/topics/ANSWERS/2003/ANS01200.html.

Beers, M. H.