Heart attack diagnosis

If you are in an emergency room after experiencing symptoms of a heart attack, you will be asked about your symptoms and have your blood pressure, pulse, and temperature recorded. You will also be hooked up to a heart monitor and have tests done to determine whether you are having a heart attack. Some of the tests most commonly used to diagnose^[15] a heart attack include:

• Electrocardiogram (ECG): This is the first test used to diagnose a heart attack. An ECG records the electrical activity, rate, and regularity of your heart using electrodes attached to your skin. Injured heart muscles don’t conduct electrical impulses normally, so dips or abnormalities in these impulses may show that a heart attack has occurred or is occurring.
• Blood tests: Certain heart proteins leak into the blood after the heart has been damaged by an attack. Providers will sample your blood and test it for the presence of these enzymes.

If you have had or are having a heart attack, healthcare providers will take immediate action to treat you. These additional tests may be performed:

• Chest X-ray: Taking an X-ray image of your chest allows healthcare providers to check the size of your heart and coronary arteries and to look for the presence of fluid in your lungs.
• Echocardiogram: This test uses ultrasound (high-frequency sound waves) to create a picture of the heart. An echocardiogram can help identify whether areas of your heart have been damaged and are not pumping normally.
• Cardiac catheterization: Cardiac catheterization is a procedure that examines how well the heart is working. This test checks the inside of your arteries for blockage by injecting a liquid dye into your coronary arteries through a thin, flexible tube. This dye makes the arteries visible on X-ray, revealing any areas of blockage.
• Exercise stress test: In the days or weeks after a heart attack, you may have a stress test to measure how your heart and blood vessels respond to physical exertion. This type of test measures the health of your heart by how it responds to exertion. You may be given an intravenous drug or be asked to walk on a treadmill while attached to an ECG machine that monitors your heart activity. In some cases, stress tests may sometimes also be done while wearing a mask that measures the ability of your heart and lungs to take in oxygen and expel carbon dioxide.
• Cardiac CT or MRI: These tests can be used to diagnose heart problems as well as the extent of the damage caused by a heart attack. During a cardiac CT scan, you lie on a table inside a doughnut-shaped machine. An X-ray inside the machine rotates around your body and takes images of your heart and chest.

In a cardiac MRI, you lie on a table inside a tubelike machine that produces a magnetic field. This aligns the atomic particles in some of your cells. When radio waves are broadcast toward these aligned particles, they produce signals that vary according to the types of tissues they are, creating images of your heart.

Types of heart attacks

Heart attacks can be caused by^[16] either complete or partial blockages. These are referred to in the following ways:

• A complete blockage is known as a STEMI (ST-elevation myocardial infarction).
• A partial blockage is called an NSTEMI heart attack (non-ST-elevation myocardial infarction).

While they do overlap, the diagnosis of STEMI and NSTEMI heart attacks differs slightly. Your healthcare provider or emergency specialist will determine what diagnosis and treatment are right for your condition.