What Is an Electrocardiogram?
An electrocardiogram -ecg , or ECG, is a simple, painless test that records the heart’s electrical activity. .
With each heartbeat, an electrical signal spreads from the top of the heart to the bottom. As it travels, the signal causes the heart to contract and pump blood. The process repeats with each new heartbeat. The heart’s electrical signals set the rhythm of the heartbeat.
An ECG shows:
- How fast your heart is beating
- Whether the rhythm of your heartbeat is steady or irregular
- The strength and timing of electrical signals as they pass through each part of your heart
This test is used to detect and evaluate many heart problems, such as angina heart attack, rhythm disturbances,etc..
ECGs also are used to monitor how the heart is working.
Who Needs an Electrocardiogram?
You are recommended an electrocardiogram (ECG) if you have signs or symptoms that suggest a heart problem. Examples of such signs and symptoms include:
- Chest pain
- Heart pounding, racing, or fluttering, or the sense that your heart is beating unevenly
- Problems in breathing
- Feeling tired and weak
You may need to have more than one ECG so your doctor can diagnose certain heart conditions.
An ECG may be done as part of a routine health exam. The test can screen for early heart disease that has no symptoms. .
You may have an ECG so your doctor can check how well heart medicine or a medical device, such as a pacemaker, is working.
The test also may be used for routine screening before major surgery.
Your doctor may use ECG results to help plan your treatment for a heart condition.
No special preparation is needed for an electrocardiogram (ECG). Before the test, let your doctor or doctor’s office know what medicines you’re taking. Some medicines can affect ECG results.
An electrocardiogram (ECG) is painless and harmless. A technician attaches soft, sticky patches called electrodes to the skin of your chest, arms, and legs. The patches are about the size of a quarter.
After the patches are placed on your skin, you lie still on a table while the patches detect your heart’s electrical signals. A machine records these signals on graph paper or displays them on a screen.
Special Types of Electrocardiogram
The standard ECG described above, called a resting 12-lead ECG, records only seconds of heart activity at a time. It will show a heart problem only if the problem is present during the time that the test is run.
Many heart problems are present all the time, and a resting 12-lead ECG will detect them. But some heart problems, like those related to an irregular heartbeat, can come and go. They may occur for only a few minutes out of the day or only while you exercise.
Special ECGs, such as stress tests and Holter and event monitors, are used to help diagnose these kinds of problems.
After an electrocardiogram (ECG), the electrodes (soft patches) are removed from your skin. You may get a rash or redness where the ECG patches were attached. This mild rash usually goes away without treatment.
You usually can go back to your normal daily routine after an ECG.
Many heart problems change the heart’s electrical activity in distinct ways. An electrocardiogram (ECG) can help detect a number of heart problems.
ECG recordings can help doctors diagnose a heart attack that’s happening now or has happened in the past. This is especially true if doctors can compare a current ECG recording to an older one.
An ECG also can show:
- Lack of blood flow to the heart muscle
- A heart that’s beating too fast, too slow, or with an irregular rhythm (arrhythmia)
- A heart that doesn’t pump forcefully enough (heart failure)
- Heart muscle that’s too thick or parts of the heart that are too big
- Birth defects in the heart (congenital heart defects)
- Problems with the heart valves (heart valve disease)
- Inflammation of the sac that surrounds the heart (pericarditis)
An electrocardiogram (ECG) has no serious risks. It’s a harmless, painless test that detects the heart’s electrical activity. ECGs don’t give off electrical charges, such as shocks.
What are the limitations of the ECG?
· The ECG reveals the heart rate and rhythm only during the time that the ECG is taken. If intermittent cardiac rhythm abnormalities are present, the ECG is likely to miss them. Ambulatory monitoring is needed to record transient arrhythmias.
· The ECG can often be normal or nearly normal in patients with undiagnosed coronary artery disease or other forms of heart disease (false negative results.)
· Many “abnormalities” that appear on the ECG turn out to have no medical significance after a thorough evaluation is done (false positive results
Key Points
- An electrocardiogram (ECG) is a simple, painless test that records the heart’s electrical activity.
- An ECG shows:
- How fast your heart is beating
- Whether the rhythm of your heart is steady or irregular
- The strength and timing of electrical signals as they pass through each part of your heart
- ECGs are used to detect and evaluate many heart problems, such as heart attack, arrhythmia, and heart failure.
- Your doctor may recommend an ECG if you have signs or symptoms that suggest a heart problem. An ECG also may be done as part of a routine health exam, to check how medicine or a medical device is working, or for routine screening before major surgery. Your doctor may use ECG results to help plan your treatment for a heart condition.
- No special preparation is needed for an ECG. Before the test, let your doctor or doctor’s office know what medicines you’re taking. Some medicines can affect ECG results.
- For an ECG, soft, sticky patches called electrodes are attached to the skin of your chest, arms, and legs. You lie still on a table while the patches detect your heart’s electrical signals. A machine records these signals on graph paper or displays them on a screen. The entire test takes about 10 minutes.
- If you have a heart problem that isn’t present all of the time, you may need a special type of ECG, such as a stress test or Holter or event monitor.
- You usually can go back to your normal daily routine after an ECG.
- Many heart problems change the heart’s electrical activity in distinct ways. An ECG can help detect a number of heart problems. Results from an ECG can suggest problems such as lack of blood flow to the heart muscle, problems with heart rhythm or the heart’s pumping action, birth defects, problems with heart muscle or heart valves, and inflammation of the heart.