Heart Attack

Diagnosis

When a heart attack occurs, speed of diagnosis and intervention is essential. The patient is first asked how he or she feels, and medical personnel listen to the heart and breathing and gather information about past medical and family history. With this information, paramedics or emergency room personnel can usually diagnose a heart attack.

At this point, Mayo Clinic emergency room personnel transfer the patient rapidly to the cardiac catheterization laboratory, where cardiologists first find the blockage using coronary angiogram. A thin, flexible tube (catheter) is threaded through an artery from the groin and into the arteries of the heart. A dye is injected through the catheter and blockages can be seen on a special X-ray screen.

After finding the blockage, the interventional cardiologist typically performs catheter-based intervention to open the artery and restore oxygen and nutrients to the heart muscle. (See treatment options for more details.)

If the diagnosis is in question or a more definite diagnosis is needed, these tests are used to determine if a heart attack is in progress:

• Electrocardiogram (ECG or EKG) - This noninvasive test measures electrical signals created by the heart as it beats. An injured heart muscle does not beat normally, and the ECG usually indicates the abnormality.
• Blood tests - Certain heart enzymes slowly leak into the bloodstream if the heart has been damaged by a heart attack. A blood test identifies that these enzymes resulted from a heart attack.

After immediate diagnosis and intervention, patients are transferred to the Coronary Care Unit (CCU) where additional tests are performed to examine the aftereffects of the heart attack:

• Chest X-ray - An X-ray shows the size and shape of the heart and its blood vessels.
• Nuclear scan - Trace amounts of radioactive material, such as technetium, are injected into the bloodstream and can be viewed with special cameras. The material is absorbed by healthy heart muscle cells, so any abnormalities are visible to heart (cardiac) specialists.
• Echocardiogram - This noninvasive test uses ultrasound technology to view the beating heart and its chambers.