Previous article "" caused discussion.
Some readers asked, what should I do if the ECG is straight after the heartbeat stops? Do you still want defibrillation?
Then some readers said that when the heart stops beating, it is motionless, and the electrocardiogram is a straight line.
Here, the first reader asked a reasonable question, and the second reader had a misunderstanding.
When the heart stops beating and does not beat, the ECG is not always a straight line.
An electrocardiogram is a record of the bioelectric activity of cardiomyocytes. The heartbeat, the heartbeat of the heart, is produced by the uniform and orderly contraction of cardiomyocytes after receiving the ECG command.
With bioelectricity, the ECG can have performance; while the cardiomyocytes cannot contract and relax in a unified and orderly manner, the heart will not beat (jump). Therefore, when the heart is not beating, there can also be ECG activity, and the ELECTROG can have a pattern.
Let's talk about what the ECG will show when the heart is stopped, and under what circumstances is electrical defibrillation required.
When the heart stops beating, that is, when the beat stops, there are three manifestations of the electrocardiogram that reflects the electrical activity of the heart muscle.
The first, as we have all heard, is ventricular fibrillation, the full name is "ventricular fibrillation."
Normally, the ventricles of the heart are responsible for delivering blood to the aortic arteries. The ventricular myocardium should contract synchronously under the unified command of ECG. In this way, a consistent force is formed, pumping the blood out of the heart and transporting it to the aorta and then to the whole body.
What about ventricular fibrillation? It is the electrical activity and contraction of the ventricular muscles that are chaotic. The electrical activity of cardiomyocytes is independent, and the contraction of cardiomyocytes is also independent. You contract, I contract, not synchronized, the entire ventricular muscle becomes peristalsis, naturally it can not form a synergy, the heart's ejaculation will stop. Such a heart, there is electrical activity, but it is chaotic; the heart muscle is still contracted, it is also chaotic, it cannot pump blood, it stops beating.
Therefore, when ventricular fibrillation, the heart does not beat, but there is electrical activity and myocardial contraction.
At this time, the ECG performance is a large and small, curved waveform, and the term of the ECG is called the "f" wave, that is, the ventricular fibrillation wave.
This condition generally occurs early in cardiac arrest, especially cardiac arrest. There are sudden illnesses or sudden blows to the heart, such as acute myocardial infarction, asphyxiation, trauma, or cardiac arrest caused by electric shocks and drowning. Therefore, in the early stages of cardiac arrest, special emphasis is placed on electrical defibrillation.
In the second case, there is an ECG waveform, but the myocardium does not contract, which is medically called "electrical-mechanical separation".
Electricity, that is, electrocardiogram, mechanical, is the ability of the heart muscle to contract. Electrical-mechanical separation, that is, there is an ecglyctic, no myocardial contraction, the same is cardiac arrest.
At this time on the ECG, you can see an abnormal heart wave, the QRS wave group of the ventricle, the broad deformity, slow, but the patient's heart is not beating, no heart sounds, no circulation. This condition is usually a terminal patient with chronic failure, or a patient with a prolonged cardiac arrest.
In the third case, the electrical activity of the heart muscle is completely gone, and the heart naturally does not contract. This is medically called "ventricular pause."
At this time, the ECG is a straight line, or there can be atrial waves. This situation is generally the end of the day.
Understand the three ECG conditions during cardiac arrest, and then look at "defibrillation".
Now it is very clear that defibrillation, in addition to the "ventricular fibrillation", the first case mentioned above. In patients with ventricular fibrillation during cardiac arrest, electric shock defibrillation is used to eliminate ventricular fibrillation and restore the heartbeat. Ecglyctic-mechanical separation and ventricular pause are not suitable for defibrillation.
When defibrillation occurs, the instrument discharges through two electrode plates or electrode plates that are close to the patient's skin, which is direct current, so that the current passes through the patient's heart. In this way, a unified electric shock discharge stops the chaotic electrical activity of cardiomyocytes during ventricular fibrillation. Then, the electrical activity of the cardiomyocytes is restarted, and it can come out of the uniform pace, contract synchronously, and the heart will re-beat.
ECG defibrillation doesn't necessarily work once, sometimes multiple times, supplemented by continuous cardiac compressions, ventilation and oxygenation, and drug support.
About "Should I defibrillate when the ECG is in a straight line"?
Everyone has done an electrocardiogram. When doing the ELECTROCARDI, the limbs will be connected to the wires, and the chest wall will also be sucked up with small balls and connected to the wires, which are different electrodes, responsible for inducing ECG signals in various parts and directions. EcGs in different directions are not the same, so there are many patterns on the ECG, width, width, height, shape, etc., but in fact there is a certain law.
However, on the monitor screen of the defibrillator, only one or three leads can often be seen, so that the ECG situation reflected is not comprehensive. Therefore, in the early stage of cardiac arrest, the ECG seen by the single lead is a straight line to allow blind defibrillation, because the single lead may have omissions.
And when the cardiac arrest occurs, the most common condition is ventricular fibrillation, more than 90%. For ventricular fibrillation, electric shock defibrillation is most effective, and as early as possible. For every 1 minute delay in electric shock defibrillation, the success rate of defibrillation decreases by 7 to 10%. If ventricular fibrillation cannot be removed in time, it will soon turn to ECG stillness and ventricular pause.
Therefore, if the heart stops beating for a long time, the straight line of the electrocardiogram is a straight line.
(All rights reserved, may not be reproduced without my authorization!) ）