Defibrillation is the act of defibrillating the heart to treat the heart when it is not pushing blood because the heart muscle is not working in any pattern. Electricity causes a muscle to contract, this is how nerves cause muscles to work. The heart is a large muscle, and certain parts need to contract before other parts in order to push blood through the heart and out to the rest of body correctly. Sometimes the heart muscle doesn't contract in the correct way or at the correct speed, this is called an "arrhythmia" (out of rhythm). Fibrillation is a type of arrhythmia when the whole heart is quivering, not organized to make heart beats of any kind. CPR (Cardiopulmonary resuscitation) can get blood to the body when the heart is fibrillating, but the heart still needs to be restarted. Sometimes CPR will do that as well, but often a defibrillator is needed. Defibrillation is done with a defibrillator.
Defibrillation works by carefully sending a strong electric current to the heart, which "resets" the heart, and hopefully returns a normal, coordinated heart rhythm. It needs to depolarise (take away the existing electric charge) from a large part of the heart muscle, which stops the arrhythmia and allows the normal heartbeat to return. Defibrillators can work outside the body with the use of an external defibrillator or an automated external defibrillator, or inside the body with an implantable cardioverter-defibrillator.
The first use of the technique on a human was in 1947 by Claude Beck, a professor of surgery at Case Western Reserve University. The patient was a 14-year-old boy named Mickey.
Defibrillation is now used during open heart surgery, when the heart is stopped on purpose. In1980 the first implanted defibrillator was put into a patient. Implanted defibrillators are put into the chests of people at risk of going into fibrillation.
Not all arrhythmias need defibrillation. Some arrhythmias still push blood to the body, not well, but still enough to keep a person alive. Other types, like ventricular fibrillation or pulseless ventricular tachycardia, will cause a person to die within minutes unless treated. These are what need to be treated by defibrillation.
Fibrillation is when the heart muscle is contracting, but not in any organized way, and blood is not pumped. Pulseless tachycardia is when the heart is beating too fast to collect any blood to push.
Asystole is when the heart is not working at all (flat-line). Defibrillation does not work on asystole, but CPR might help.
Defibrillation is most successful when done right when the problem starts. Success in the first minute is about 90% and drops by 10% every minute after that. This time can be made longer by giving the person CPR, but having a defibrillator close by is very important.
Defibrillator
A defibrillator is a machine that can help when ventricular fibrillation happens in the heart of a human. A defibrillator is a life saving device.
Fibrillation happens when many different cells in the heart begin to act as pacemaker cells. This means that many thousands of cells tell the heart to beat, all at different times and with no rhythm. This confusion causes the heart to become unable to move blood around the body. This causes cardiac arrest and death.
A defibrillator sends a high energy pulse from the top-right of the heart to the bottom-middle of the heart. This causes the whole heart to stop all activity. The heart's normal pacemaker then can try and restart normal beating. Defibrillation does not always work.
Implantable cardioverter-defibrillators (ICD) are defibrillators that are designed to help patients from inside their body. They are put inside people that are at high-risk of going into cardiac arrest and monitor a person's heart rate, rhythm, and waveform. By comparing the activity in the different chambers of the heart, an icd can detect cardiac arrhythmias and treat them quickly.
External defibrillators are often used in hospitals and ambulances. They are now also being used outside of medical environments more as automated external defibrillators (see below) become safer and cheaper. There are many different types of external defibrillators, and progress in cardiac research has led to big improvements in the underlying technology.
Until the 1990s, external defibrillators relied on monophasic ("one phase") shock waves. Electrical pulses are quickly sent from one electrode to the other in one direction.
Biphasic ("two phases") defibrillation, however, changes the direction of the pulses. It completes one cycle in approximately 10 milliseconds. This means less energy is needed for successful defibrillation. That means less risk of burns and other damage. The small capacitor ("battery") size required for the defibrillator can result in large cost and size savings.
An automated external defibrillator (AED) is a self-contained defibrillator device designed to be movable, and easy and simple to use. They are often shaped like briefcases so that they can be carried by a handle. An AED contains a battery, a control computer, and electrodes. When the electrodes are stuck onto the patient, the control computer will assess the patient, checking the rhythm of their heart. It will then charge itself to an appropriate power level and tell users that the person needs to be shocked. If the patient does not need to be defibrillated, the automated external defibrillator will not allow a shock to be administered. A button must still be pushed manually to trigger the shock, as the operator beforehand must be certain that nobody is touching the patient. Often, automated external defibrillators will have speakers which give instructions when they are opened.
Current automated external defibrillator devices are designed for emergency medical technicians, home users, police and security officers and other people with minimal medical knowledge. These devices are commonly found in large gathering places, such as airports, casinos, sports stadiums, and college campuses.
The electrode is the part of the defibrillator that gives off the shock.
The most well-known type of electrode is the traditional metal paddle with an insulated handle. This type must be held in place on the patient's skin while shocks are delivered. Before the paddles are used, gel must be applied to the patient's skin so that there is a good connection and to minimise electrical resistance.
Another type of resuscitation electrode is designed as an adhesive pad which can be stuck onto the skin of a patient. These electrodes are left connected to a defibrillator. If defibrillation is required, the machine is charged, and the shock is delivered, without any need to apply any gel or to retrieve and place any paddles.
Both solid- and wet-gel adhesive electrodes are available. Solid-gel electrodes are more convenient, because there is no need to clean the patient's skin after removing the electrodes. However, the use of solid-gel electrodes presents a higher risk of burns during defibrillation, since wet-gel electrodes more evenly conduct electricity into the body.
Defibrillators are often depicted in movies, television, video games and other fictional media. This is because it can quickly produce dramatic improvements in patient health. Their function, however, is often exaggerated.
Medical providers are often shown defibrillating patients with a "flat-line" ECG rhythm (also known as asystole); this is not done in real life as the heart is not restarted by the defibrillator itself.
Curse
A curse is a word which threatens the other person to have bad luck. Nobody knows if it really works or become true. Some people believe in them even so, that they become true by magic. For example, for fairy tales, the princes are cursed to become a beast or a frog (i.e. frog prince) by witches because of their bad behaviours. But in the end a princess saves them.