Mechanism of action of electrocardiogram

This is an automatically translated article.

The article was professionally consulted by BSCK II Nguyen Quoc Viet - Interventional Cardiologist - Department of Medical Examination & Internal Medicine - Vinmec Danang International General Hospital.
Electrocardiogram is a very common test in most medical facilities today. This is a fairly simple subclinical test that does not cause complications for the patient but has a very high diagnostic value.

1. What is electrocardiogram?

An electrocardiogram (ECG) is a graph that records the changes in electrical currents inside the heart. As a non-invasive, non-invasive, and fast results.
Electrocardiogram is often used in medicine, this is a common test to detect some diseases and monitor the condition of the heart in many situations, cardiovascular diseases. The electrocardiogram is also standard equipment in the operating room and in the ambulance.

2. How does an electrocardiogram work?

The heart contracts to a rhythm and is controlled by a conduction system in the heart muscle. The electrical currents of the heart are very small, only a few thousandths of a volt, but can be detected from electrodes placed on the patient's arms, legs and chest transmitted to the recorder. These electrodes (sensors) are usually kept for several minutes. The electrical recorder will amplify the signal and record it on the electrocardiogram.
Electrocardiogram lines are shown as curved lines, up and down that vary with the rhythm of the heart's contractions. When measuring the electrocardiogram, the patient is in the supine position, so that the doctors attach the electrodes from the electrocardiogram to the heart, wrist, and ankle areas of the patient according to defined positions. These electrodes are attached to the skin and are painless during the measurement.

3. Electrocardiogram for what?

Electrocardiogram is one of the routine tests in the hospital. The purpose of an electrocardiogram examination includes:
Checking the heart rate, diagnosing heart rhythm disorders.

Diagnosing a heart attack (Coronary artery disease) Checking for abnormalities such as thickening of the heart muscle, dilation... Electrocardiogram is used to examine and diagnose cardiovascular diseases, monitor and check the status of the heart. Some patients were diagnosed with valvular regurgitation, hypertension, dyslipidemia, pericarditis... with typical symptoms such as dyspnea, angina pectoris.

4. When should ECG be measured?

Electrocardiogram may be indicated by the doctor in the following cases:
Examining and diagnosing cardiovascular diseases in cases where there are manifestations such as: arrhythmia, shortness of breath, chest pain. .. Check and monitor the status of patients diagnosed with diseases such as: heart failure, open heart valve, myocardial ischemia, myocardial infarction, patients with hypertension, diabetes ... Screening for risk of cardiovascular diseases Preparing for surgery...

5. Limitations of Electrocardiogram

The electrocardiogram is a simple and valuable test. Sometimes an electrocardiogram can definitively diagnose a heart condition. However, in some cases, an electrocardiogram cannot rule out serious cardiac conditions. For example, if an irregular heartbeat appears and disappears, the ECG will be recorded at normal intervals between irregular rhythm occurrences.
Also, not all heart attacks can be detected with an electrocardiogram. Common heart disease such as angina also cannot be detected by routine electrocardiogram. Specialized ECG measurement sometimes helps to overcome some limitations of routine ECG, which are:
Stress ECG: performed during exertion (running on a roller mat or cycling). This helps assess the severity of the blockage of the coronary arteries causing the angina. Ambulatory ECG: The patient will wear a small machine that continuously records the heartbeat. This method records the electrical activity of the heart while walking (ambulatory) and performing normal daily activities in order to detect abnormal heart rhythms, which may appear and then disappear. Electrocardiographic activity is usually recorded for 24-48 hours.

6. What should be kept in mind when performing an electrocardiogram?

The electrocardiogram takes about a few minutes. Your doctor will attach 10 electrodes with adhesive pads to the skin of your chest, arms, and legs. During the measurement, the person being measured will lie on their back, the electrocardiogram machine creates a graph on paper, drawing electrical impulses moving through the heart. It may take about 5 - 10 minutes to attach the electrodes and complete the test but the actual graphing takes only a few seconds. In addition to the standard ECG, your doctor may recommend other types of electrocardiograms, such as portable electrocardiograms (which check the electrical activity of the heart for 1-2 days, 24 hours a day). After the ECG, the Cardiologist will read the waveforms recorded during the test to see if the pulses are normal and let the patient know the results on the same day or at the appointment. next. The patient can resume normal activities after the ECG. Electrocardiogram test results require reading and conclusions by a cardiologist, so the physician's professional role in electrocardiography is very important.
When performing electrocardiograms at Vinmec International General Hospital, patients can rest assured because there is not only a standard procedure, modern machinery, but also a team. The team of highly skilled doctors and nurses across the country, thus giving accurate diagnosis results, greatly contributes to the identification of the disease and the stage of the disease.
Doctor Nguyen Quoc Viet has more than 20 years of experience in the examination and treatment of cardiovascular diseases and Cardiovascular Interventions (Including angiography, dilation, stenting of coronary arteries, renal arteries...), placing temporary, permanent pacemaker... Before working at the Department of Medical Examination & Internal Medicine, Vinmec International General Hospital Da Nang, the doctor used to work for a long time at Da Nang Hospital.

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