Diagnostic Testing & Imaging
What is an electrocardiogram?
An electrocardiogram - also called an EKG or an ECG - is a noninvasive test that is used to measure the electrical activity of the heart. It can be used to help diagnose numerous cardiac conditions or to monitor heart health. As a diagnostic technique, an electrocardiogram test is typically performed in a clinic and takes around 5 to 10 minutes.
How does an electrocardiogram test work?
The heart has its own electrical system that synchronizes the heart to contract in rhythm and pump blood. Every heartbeat creates a pattern of electrical activity that can be detected with an electrocardiogram machine. During an EKG, electrodes (small patches that stick to the skin) are placed on the chest, arms, and legs and hooked up to an electrocardiogram machine. The machine records the heart’s electrical activity, and the results are read by a cardiologist.
To help better understand the condition of your heart, an EKG may also be used to measure your heart’s response to stress. In this case, your cardiologist may have you exercise on a treadmill or use intravenous drugs to induce stress.
What is an electrocardiogram used for?
A trained cardiologist can learn a lot about your heart from the results of an electrocardiogram. An electrocardiogram is used to help diagnose several cardiac conditions and heartbeat abnormalities. These include:
Myocardial infarction (heart attack)
Arrhythmias and atrial fibrillation
Structural heart disease
Valvular heart disease
A cardiologist may also use electrocardiogram results to help get to the bottom of what’s causing numerous symptoms, including:
Shortness of breath
Rapid and irregular heartbeats (also called heart palpitations)
Fainting or collapse (also called syncope)
Irregular heart sounds or heart murmurs
It is also very common for an electrocardiogram to be used to monitor the heart’s electrical activity to observe:
Known cardiac arrhythmias
The effects of certain medications on the heart
The effects of anesthesia before or during a procedure
The heart’s activity during cardiac stress testing
Ambulatory rhythm monitoring
Sometimes your cardiologist needs more information on the electrical activity of your heart, or your symptoms do not present during your initial electrocardiogram test. In this case, your cardiologist may suggest ambulatory rhythm monitoring.
 Kligfield, P., Gettes, L. S., Bailey, J. J., Childers, R., Deal, B. J., Hancock, E. W., … Wagner, G. S. (2007). Recommendations for the Standardization and Interpretation of the Electrocardiogram. Journal of the American College of Cardiology, 49(10), 1109–1127.