Sudden Cardiac Arrest Diagnosis Information for Patients

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If a patient experiences sudden cardiac arrest, it is always a medical emergency. If the patient survives, the patient’s doctor will want to investigate to determine the cause. In order to determine the cause, the doctor will need to make a sudden cardiac arrest diagnosis. By making this diagnosis, the doctor may be able to help prevent the patient from experiencing this again in the future.


This diagnostic test is commonly given after this occurs. Sensors placed strategically on the body can detect the heart’s electrical activity. It measures the duration and timing of each electrical phase of the heartbeat and can show if there are any heart rhythm disturbances. It can show if a heart attack occurred due to the fact that when heart muscle is injured, it does not conduct electrical impulses as it should. This test can detect prolonged QT interval, and other abnormal electrical patterns, that are known to increase a patient’s risk of sudden death.

Blood Tests

Blood tests are a common component of a sudden cardiac arrest diagnosis. A cardiac enzyme test is often done to determine if a heart attack occurred by looking to see if specific heart enzymes leaked into the blood that will if a heart attack damaged the heart. It is important to know whether the patient suffered a heart attack because they can trigger this condition.

An electrolyte test can be done to measure electrolyte levels, such as calcium, potassium, and magnesium. These minerals are necessary to create electrical impulses. If an imbalance is present, the risk of arrhythmia and sudden cardiac arrest is increased.

A drug test is sometimes done to determine if a certain drug, or drugs, could have caused an arrhythmia that can result in sudden cardiac arrest. Both legal and illegal drugs can cause this.

A hormone test is sometimes done to look for a condition known as hyperthyroidism. This condition may sometimes trigger a sudden cardiac arrest.

Imaging Tests

A chest x-ray can be performed to look at the heart’s shape and size, as well as the blood vessels. It can also help to determine whether the patient has heart failure.

A nuclear scan, often performed with a stress test, can help to identify if the patient’s heart has any blood flow problems.

An echocardiogram can produce an image of the heart through the use of sound waves. This can help to find any heart damage associated with a heart attack, and is therefore, not pumping at peak capacity or normally. It can also help to look for possible valvular abnormalities.

Electrical System Testing and Mapping

This is not a commonly performed test, but it can be useful when the reason a person experienced a sudden cardiac arrest has not been identified. This test can help to determine where an arrhythmia starts.

Ejection Fraction Testing

This test is beneficial in seeing how well the heart is pumping blood and to determine a person’s risk of sudden cardiac arrest. If a patient’s ejection fraction is less than 40 percent, their risk of this condition is increased.

Coronary Catheterization

Also referred to as an angiogram, this diagnostic test can help to show if a patient’s coronary arteries are blocked or narrowed. Along with ejection fraction testing, this test can help to determine a patient’s risk of experiencing this condition.

Resources (2010). Sudden Cardiac Arrest Tests and Diagnosis. Retrieved on September 12, 2010 from

National Heart Lung and Blood Institute. (2009). What is Sudden Cardiac Arrest? Retrieved on September 12, 2010 from the National Heart Lung and Blood Institute: