- The electrocardiogram (ECG) is a diagnostic test to record the electrical activity of the heart. An ECG detects the tiny electrical impulses produced by the heart to make it contract.
- An ECG is commonly used to establish a baseline evaluation of a person’s heart, to detect abnormal heart rhythms, and to investigate newly evolving symptoms, such as chest pain, shortness of breath, or palpitations.
- Physicians use different forms of ECG testing, including resting, stress, and ambulatory ECG.
- A resting ECG may be done first because it may show a heart problem that would make an ECG stress test unsafe.
During electrocardiography (ECG), electrical signals from each heartbeat are transmitted from electrodes on the patient’s skin to a machine that creates a graph of the rhythm and rate of the heartbeat.
ECG helps physicians evaluate the following:
- Locate areas of the heart that receive an insufficient blood and oxygen supply,
- Reveal heart rhythm abnormalities,
- Evaluate a person’s prognosis after a heart attack, and
- Verify the effectiveness of medical and surgical therapies.
- Resting ECG – This test is usually performed while a patient lies on a table,
- ECG stress test – The stress test monitors a heartbeat during exercise, most commonly while a person walks on a treatmill.
- Ambulatory ECG - This test records the electrical activity of the heart while a patient does usual activities. For example, the patient may wear a Holter monitor, a battery-operated portable device that measures heart activity continuously for 24 hours, or several days, or even weeks.