How does pacemaker work?
Author Ольга Кияница
The pacemaker is an artificial rhythm driver that is implanted by medical indication. The very first pacemaker was made in 1927 and was originally located outside. This main disadvantage was supplemented by the short-term durability of the device, its service life was no more than 24 months.
Today, the pacemaker is implanted with an atrioventricular blockade, syndrome of weakness of the sinus node, arrhythmias of the heart, which are dangerous for sudden cardiac arrest.
There are various methods for stimulating cardiac activity, as well as different models of pacemakers, which today are subject to the marking system. In accordance with similar designations, a technical passport is issued for the instrument used, which specifies all characteristics of its operation.
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The principle of pacemaker action
First of all, it depends on the design of the device and the mode of operation of the pacemaker. Understanding these technical details, you can get an answer to the question of how the pacemaker works.
The basic principle of the action of the EC:
- Condition of rest - the device does not send impulses to the heart, because the work of the organ is within the normal range.
- Activity mode is the supply of an electrical impulse through the electrodes of the heart muscle, which is provoked by a heart failure or a cardiac rhythm disturbance.
- Tracking mode - not observed in all models of the EKS. Provides the ability to record the work of the heart with subsequent transfer to doctors for further analysis. In this mode, the ECC will more quickly utilize the available charge, which is simultaneously used to supply electrical impulses.
Using a recording device on a pacemaker, such disorders of the rhythm as atrial fibrillation, atrial fibrillation, various forms of tachycardia, ventricular and atrial changes in the rhythm, ventricular fibrillation can be detected.
Only the cardiologist, who after careful examination of the patient makes a conclusion about the presence of indications for implantation, is involved in the selection of the EKS.
How does heart pacemaker interact?
Artificial rhythm drivers in their first modifications worked continuously, continuously generating electrical impulses.Modern models work on demand, that is, they only stimulate the myocardium when there is a violation of the rhythm.
Often the device triggers when the heart rate is lowered. If the heart rate increases, the device is in the waiting state (detection), but this does not mean that it has broken down. With such an assumption often seek medical assistance, but it is enough to check the EC programmer to make sure it is working.
Some patients may experience an "addiction" effect during prolonged use of the pacemaker. That is, if at the beginning of the disease EKS only required occasionally to send signals, then with the progression of pathology, stimulation reaches almost 100%.
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Does the pacemaker work?
The experience of many patients shows that after the implantation of the rhythm driver, the first time the EC experience is felt. It can be a feeling of humor, vibration, twitching. Sensations become more expressive when lying on the left side.If the device is embedded on the right side, then feelings will be strengthened on the right side.
After one to two months after the implantation of the EKS, the unpleasant sensations from the instrument run.
Enhancing or causing unpleasant sensations of the device's activity can be active physical exercise. For example, some athletes experience a feeling of buzz in the chest after swimming at 900-1000 m.
The feelings of the work of the EKS depend on the mode of its activity. If the heart rhythm is normalized due to the occurrence of tachycardia, then the operation of the device can only be felt when the irregular rhythm develops. In a state of rest, patients on ECS are simply forgotten.
In the case of a two-chamber pacemaker, the matter is different, since even the cardiologist himself can not accurately characterize the operation of the device. The only thing the programmer can do in this case, whereas on the ECG one can only say about the mode in which the device is - expectations or activity.
Special modes of pacemaker operation
There are many different ECS labels that are made according to the NBG code. This separator takes into account the following parameters:
- item number - from 1 to 5;
- category - stimulated and detective chamber, response to incoming pulse, characteristics of adaptation to frequency, characteristics of reaction to tachycardia.
- Device code, which is based on abbreviations of English notation (A trium, atrium, V - ventricle, ventricles, D - dual, two heart chambers, most often atrium and ventricle, I - inhibition, prohibited, T - triggering, trigger, R - substitutes in four-digit codes and means frequency adaptation.
Five-digit codes are often related to those devices that are used to eliminate tachycardia. If the letter E is indicated, it means external regulation of the cardiac activity (externally controlled), N - stimulation is characterized as normal (normal rate competition), B - impulses are given by burst stimuli, S - pulses are given in pairs or as single ( single or doubletimed stimuli).
The code may indicate the nature of the programming. If there is a letter M, then it is a question of the multiple adjustment of various parameters (sensitivity, frequency, stimulation). The letter P stands for standard programming, taking into account output parameters or frequency. The letter О in the code indicates that there is no programming.
The most common modes of stimulation are:
- AAI - Atrial stimulation, single chamber, on demand.
- AAIR is similar + frequency adaptation.
- VVI - ventricular stimulation, single chamber, on demand.
- VVIR - Similarly + frequency adaptation.
- DDD - ventricular-atrial stimulation, bioregulable, on-demand.
- DDDR - Similar + frequency adaptation.
It is important to understand that the pacemaker can not cause a broken heart to contract. In order to trigger impulses supplied by the device, the heart muscle should be blood cooled. In addition, the myocardium itself should be in a normal state. Therefore, after the death of the patient EKS can not start the heart.
The process of pacemaker installation is not as complicated as it may seem. Today, this manipulation is equated to an operation to remove appendicitis. More questions arise in patients how to live, after the installation of ACS, but the process of surgical intervention itself is important.
In diagnostics of cardiovascular diseases an important role is played by timely diagnostics. It is often enough to conduct a standard ECG to make a correct diagnosis. In other cases, a diverse study of the heart is required, which allows you to establish the exact cause of the illness and conduct an effective treatment.