Electrocardiography
The heart muscle consists of four main chambers, called the upper chambers of the athenae and the lower abdomen. In the resting state of the heart cells there is no electrical activity in them, so the cells are polarized, and when the sinus node or the so-called pacemaker responsible for regulating the heartbeat by firing a nerve, this pass through the atria and cause the removal of polarization And then spread to the ventricles as well, after reaching another node located between the atria and ventricles. This node causes a slight delay in the contraction of the ventricles until the ears are completely devoid of blood.
After the end of the depolarization wave, the heart cells undergo a re-polarization wave, which corresponds to the relaxation of the cardiac cells. The ECG records this electrical activity at all stages, amplifying the waves to be recorded on a paper. The ECG is performed by installing several electrodes on Arms, feet and chest, thanks to the invention of the device of electrocardiography of the heart to several scientists, it went through many stages of development, beginning with the world Galvani, and then the scientists Gabriel Leibman, Matioshi and Augustus and Rr in turn developed this device is very important, even stepped T World Willem Einthoven this device until it reached us in its current form.
ECG is usually performed to detect irregular heartbeat, as well as to diagnose the causes of chest pain, especially to check for a heart attack.
Electrophysiological analysis of the heart
The 12-pole electrocardiogram is the most commonly used cardiology diagnostic tool. This is done by placing these electrodes on the patient’s body, each pole in its specific position, after lying on the patient’s back. By following some techniques and analytical methods, there are several things that are revealed by electrocardiogram:
- Heartbeat: The normal heartbeat in a healthy person ranges between 60 and 100 beats / minute, and the minimum may be reduced to 50 in athletes. If the pulse rate is more than 100, the person has an acceleration in the heartbeat, but less than 60 beats / minute means that the person has a slow heartbeat. The ECG is measured by calculating the distance between consecutive QRSs.
- Pacemaker systems: either normal or disordered.
- Wave P: This wave reflects the depolarization of the atria, ie the contraction of the atria.
- P-R: This period represents the time between the depolarization of the stepmaker until the depolarization of the ventricles begins.
- Compound QRS: This compound represents the removal of polarization from the ventricles.
- ST Section: This section represents the interval between depolarization and re-polarization of the ventricles. This section is very important in the diagnosis and treatment of coronary artery disease. Accordingly, patients with a heart attack are divided. Some of them have myocardial infarction without the height of the ST section, and there are patients with myocardial infarction with the height of the ST section.
- QT Period: This period represents de-polarization and re-polarization of the ventricles. It is inversely related to the speed of the heartbeat, and the heart rate accelerates accompanied by a short period of QT and vice versa.
- Electrophysiological axis of the heart: Reflects the vector of electrical activity of the heart, it may be normal or oblique to the left or to the right.
Uses of electrocardiography
Doctors use electrocardiogram to detect many heart conditions when the patient complains of chest pain, rapid heartbeat, dizziness, or shortness of breath. The accuracy of the electrocardiogram is based on the suspected condition Some do not cause any changes in ECG, and with a normal heart layout, it does not mean exclusion of heart disease. Some arrhythmias appear and disappear at intervals, and there may be no signs of their presence in ECG, nor are all seizures Heart attack may change On the electrical planning for the heart.
ECG may be performed for patients undergoing surgery, or for those with a family history of cardiovascular disease. In addition, it may be used for patients taking heart-damaging drugs. A series of electrocardiographs may also be conducted to monitor the health status of cardiovascular patients, as well as to detect the effect of certain medications or devices used to improve the performance of the heart muscle. Cardio-arrhythmias appear when suffering from many heart diseases, such as heart attacks, whether old or recent, coronary heart disease, heart arrhythmias such as rapid, slow or irregular, as well as changes in the levels of certain elements in the blood such as potassium and calcium, As well as congenital heart defects, myocardial hypertrophy, and pericardial effusion, the collection of fluid in the membrane surrounding the heart, as well as myocarditis.
Types of electrocardiogram
There are three main types of electrocardiogram, and the choice of type depends on the symptoms of the patient, as well as the suspected condition. The types of electrocardiogram are as follows:
- ECG at rest: It is required to perform this type lying patient on the back in a relaxed position.
- ECG during the effort: This type is performed during the patient’s use of a treadmill or exercise bike. It is used for patients with symptoms of physical exertion.
- ECG Mobile: This is done by installing the electrodes on the patient’s body, and connecting them to a small device placed on his or her side, thus monitoring the condition of the heart home. This type is reported in cases where the patient suffers from unexpected symptoms that occur at random times.