Diagnosing a Heart Attack

One test often used to help diagnose a heart attack is an electrocardiogram. You might hear this test called an ECG or an EKG. It is a quick, painless test that provides valuable information about the heart’s electrical activity. This EKG was performed in the emergency room. The shape and size of the “waves” on this EKG led the emergency room doctor to be concerned that the patient might have a blocked artery in the heart. A blocked heart artery can cause a heart attack, which is a medical emergency requiring immediate treatment by an interventional cardiologist.

Heart attack diagnosis can take place beginning at any one of several points: in the ambulance on the way to the hospital, in a hospital’s emergency room, or at the hospital after a heart attack has already taken place. The medical professionals who treat you at any of these stages will use symptom evaluation and tests to diagnose a heart attack.

The tests commonly used to diagnose a heart attack are electrocardiogram (ECG/EKG), blood tests, echocardiogram, and cardiac catheterization/angiogram. CT coronary angiogram also may be used.

Electrocardiogram (ECG/EKG). An electrocardiogram, also called an ECG or EKG, is a quick, painless test that measures the heart’s electrical activity and records any disturbances in heart rhythm. You may have seen images of an ECG readout on television or in movies: the electrical activity image looks like a line graph with peaks and valleys. The shape and size of these waves, the time between each wave and the rate and regularity of the heartbeat provide valuable information to doctors. An ECG can help doctors detect heart muscle damage from a heart attack.

Blood tests. Certain substances in the blood can help doctors identify if a patient has had a heart attack. When the heart muscle is damaged, it releases particular enzymes and proteins into the bloodstream. A common blood test to check for a heart attack is one to identify the presence of the protein troponin. After a heart attack, troponin levels may be high for one to two weeks, making it good for diagnosing heart attacks after they have occurred. However, troponin levels may be high for non-cardiac reasons as well, most commonly renal (kidney) failure. Creatinine kinase (CK) and CK-MB are other blood tests also used to assess for a heart attack. CK is an enzyme in muscle tissue throughout the body, including the heart, and CK-MB is an enzyme more specific to the heart.

Echocardiogram. Echocardiography uses ultrasound waves to make a picture of structures moving inside the heart. These harmless sound waves travel from an instrument, called a transducer, placed on the chest and left rib cage. As the sound waves reflect back from structures in the heart to the transducer, the echocardiogram machine receives and interprets them – and creates a picture of the heart muscles, valves and blood vessels in motion. An echocardiogram is crucial in assessing whether all areas of the heart are contracting well. If one is having a heart attack, generally, the affected area of the heart will not pump as well as the rest of the heart.

CT coronary angiogram. Computerized tomographic angiography, also called CTA or CT angiography, uses x-rays and computers to create detailed images of blood vessels and the blood flow within them. CTA can be performed to evaluate many of the body’s arterial systems, such as the heart, the brain, or the blood vessels coursing through the chest, abdomen and pelvis. The test can help identify if blood flow to the heart is being blocked, causing a heart attack.

Cardiac catheterization/angiogram. An angiogram is a diagnostic procedure that provides detailed, x-ray pictures of your heart and its blood vessels. It is performed by cardiologists. If a stent is needed, this is then performed by a specially trained cardiologist called an interventional cardiologist. Having an angiogram requires a visit to what is called the catheterization laboratory, or “cath lab,” which is usually located in a hospital. The cath lab is equipped with an x-ray camera and a TV monitor (screen) on which the cardiologist views your heart and arteries. For the procedure, a catheter is inserted through a small puncture site in the skin and threaded through an artery to the heart, at which point a contrast dye is injected into the heart and arteries. This dye makes it possible for the x-ray camera to record a “movie” of your heart and arteries. Once a blockage has been viewed, the treatment team can decide whether the heart attack would be best treated with angioplasty and stenting or cardiac bypass graft surgery.