How Is a Heart Attack Diagnosed?

The diagnosis of heart attack is based on your symptoms, your personal and family medical history, and the results of diagnostic tests.

EKG (Electrocardiogram)

This test detects and records the electrical activity of the heart. Certain changes in the appearance of the electrical waves on an EKG are strong evidence of a heart attack. An EKG also can show if you’re having arrhythmias (abnormal heartbeats), which a heart attack (and other conditions) can cause.

Blood Tests

During a heart attack, heart muscle cells die and burst open, letting certain proteins out in the bloodstream. Blood tests can measure the amount of these proteins in the bloodstream. Higher than normal levels of these proteins in the bloodstream is evidence of a heart attack.

Commonly used blood tests include troponin tests, CK or CK–MB tests, and serum myoglobin tests. Blood tests are often repeated to check for changes over time.

Coronary Angiography

Coronary angiography is a special x-ray exam of the heart and blood vessels. It's often done during a heart attack to help pinpoint blockages in the coronary arteries.

The doctor passes a catheter (a thin, flexible tube) through an artery in your arm or groin (upper thigh) and threads it to your heart. This procedure—called cardiac catheterization—is part of coronary angiography.

A dye that can be seen on x ray is injected into the bloodstream through the tip of the catheter. The dye lets the doctor study the flow of blood through the heart and blood vessels.

If a blockage is found, another procedure, called angioplasty, may be used to restore blood flow through the artery. Sometimes during angioplasty, the doctor will place a stent (a small mesh tube) in the artery to help keep the artery open.