Implantation of a cardioverter defibrillator for cardiac arrhythmias (ventricular/atrioventricular pacemaker)
When the heartbeat is irregular, especially if the heart is racing, it is sometimes recommended to implant a special device to treat and regulate the heartbeat, which can monitor and control the movements of the heart. An automated implantable defibrillator, unlike conventional pacemakers, can treat heart rates that are not only too slow, but also too fast. The pacemaker relies on a long-life battery and works via electrodes in the heart area.
Rhythmic electrical excitation is normally generated in the heart, specifically in a small node on the right atrium called the node
sinusoidal; The heart passes it through its wall causing the heart muscle to contract, so the blood is pumped through the circulatory system. Problems in the formation and delivery of this stimulus lead to arrhythmias (arrhythmias).
Arrhythmia arises from various causes. Often the cause is caused by the heart itself, for example Heart valve changes With high pressure, or narrowing of the coronary arteries (coronary heart disease), previous heart attacks, or myocarditis. However, arrhythmias can also be caused by external causes, for example by certain substances (such as caffeine, drugs, drugs, nicotine) or by hyperthyroidism or psychological reactions that cause an irregular heartbeat.
The forms of arrhythmia vary. It is roughly divided into a very fast pulse and a very slow pulse. The normal rate for adults is around 60 to 100 beats per minute.
Many arrhythmias are asymptomatic and do not cause any harm to patients. Though, some cases can become life-threatening. With the possibility of several irregularities occurring at the same time.
Irregular, slow or accelerated heart activity is often noted directly as palpitations.
If the heart's activity is too slow (bradycardia), the blood flow in the body decreases. This is especially noticeable in the brain, which leads to fatigue and dizziness, and in some cases puts the patient at risk of losing consciousness.
If the chambers of the heart beat too fast (ventricular tachycardia), the pumping function of the individual beats is inadequate, mainly because not enough blood is able to flow into the chambers between contractions, and the blood flow to the body is reduced. Here, too, blurring, dizziness, or even loss of consciousness can occur. Breathing disturbances, sometimes angina pectoris (tightness, pain and pressure in the chest, often spreading to other parts of the body) may occur.
In ventricular fibrillation, the heart beats so fast (300 beats per minute or more) that it can no longer perform its pumping function. In terms of symptoms, this can be compared to cardiac arrest; The patient loses consciousness in a very short time. Without treatment, brain tissue destruction occurs, which within minutes progresses to an irreversible form. The patient usually dies after about 10 minutes.
There are many other forms of arrhythmia that will not be discussed here, as treatment with a defibrillator may be possible in the above cases.
Sometimes, symptoms, the patient's history and physical examination actually lead to the suspicion of a heart arrhythmia. An electrocardiogram is performed, which shows typical changes in each case. Long-term (24-hour) electromyography is also recommended to detect disturbances that are occurring only in the meantime. Sometimes other screening methods are used, for example administering the drug on an experimental basis or the so-called electrophysiological examination (EPU) using Cardiac catheterization.
Since the types of arrhythmias can have similar symptoms, they should be distinguished from each other.
Mild arrhythmias don't need treatment at all. The heart can often be returned to a normal rhythm by taking medications. For each type of arrhythmia, certain drugs are used, which are divided into four classes.
During a cardiac catheterization examination, it may make sense to cut off certain bundles by destroying the tissue with electricity, so that the abnormal excitation can no longer be transmitted.
Ventricular fibrillation is treated as an emergency with an external defibrillator, which can prevent uncoordinated excitation by short, strong electrical impulses.
If drug therapy and other possible forms of treatment are insufficient to regulate the heart rhythm, an ICD may be recommended. The device can also be implanted prophylactically if an arrhythmia that requires treatment is expected soon.
The functional principle of this device is that if the heartbeat is too slow, small electric shocks are delivered to the heart. If the heart beats too fast, the defibrillator sends a stronger current to prevent it. The device can be specially programmed to adapt to the conditions.
During surgery, a pocket is created under the collarbone under local anaesthesia. A defibrillator is inserted into them.
Once this is done, an electrode is inserted into a vein below the collarbone (subclavian vein) and inserted into the heart. The electrode of the single-chamber defibrillator is placed at the lower end of the right ventricle. If a two-chamber defibrillator is fitted, another electrode will be installed in the right atrium. The progression of the electrodes is similar to a cardiac catheterization examination and is done under fluoroscopy with an X-ray machine. Then the electrodes are attached to the defibrillator.
After the system is successfully inserted, a short sedation is initiated in which an artificial arrhythmia is used to check if the pacemaker is working. The triggered frequencies are reversed by further electrical impulses.
Possible additional procedures for operation
Sometimes it is necessary to insert additional electrodes or probes. Complications may result in the need for other unplanned measures.
There is a risk of primary or secondary bleeding. Structures in the vicinity can be damaged, such as nerves that may show symptoms of paralysis, numbness or other failures. Myocardial damage cannot be ruled out.
The lungs can also be affected under certain conditions; Defects in the pleura can lead to a buildup of air that obstructs breathing (pneumothorax). At this point, as well as around the heart, an effusion can develop, which can severely impair function. Inflammation, disturbances in wound healing, and scarring can also occur. Allergic reactions are also possible. Blood clots can form, which can lead to inadequate blood flow in different parts of the body, such as the lungs (pulmonary embolism). Problems with the defibrillator or electrodes, such as failure, displacement, or damage, cannot be ruled out.
before the operation
Medications that cause blood clotting, such as aspirin or Marcomar, must be discontinued.
After the operation
On the last day of the hospital stay, the system is checked again andAdjust it according to individual conditions with a programming device.
During the first few days after the operation, you should not make violent movements, especially in the arm on the side of which the defibrillator was operated. Exhaustion of the entire body should also be avoided. Since there is a risk of losing consciousness, you should only drive a vehicle with the approval of a doctor. Other machinery that may cause accidents should also not be operated. This can also be dangerous when swimming. Various devices and facilities can impair the function of the defibrillator.
This includes high voltage systems, electric motors, electrostimulation devices, and other devices powered by electricity or magnets. In medicine, for example, an MRI (magnetic resonance tomography) scan can have negative effects.
Regular checks of the system and heart function should be performed and the device may need to be reset. The primary battery can be used after a few years and may have to be replaced along with the pacemaker.
The doctor should be informed at short notice if any special symptoms appear that may indicate a complication or malfunction of the defibrillator.
Is the pacemaker the same as the defibrillator?
The pacemaker is the steady hand that guides your heart through each day, while the defibrillator is the guardian angel to keep you safe if your heartbeat becomes dangerously irregular.
How long can a person live with an implantable defibrillator?
Pacemakers and ICDs generally last 5 to 7 years or longer, depending on use and type of device. In most cases, you can lead a normal life with an ICD.