Question came up in one of the writer’s chats I visit yesterday:
What would happen if a major jolt of electricity passed through the brain?
A major jolt passing through the brain wouldn’t be dissimilar to passing a major jolt of electricity across the CPU of a computer. Chances are good that some smoking and very little thinking would follow. Execution by electric chair confirms that massive doses of electricity are lethal in humans, however, there are reports of humans surviving major jolts, such as in the case of lightning strike, though it’s unlikely that the current passed directly through the brain or heart.
Small doses of electricity, however, are actually used to treat the human body in a number of ways. We’ve all seen the exciting rescue (or attempt anyway) of folks on TV whose hearts have stopped working correctly. Here are a few of the ways electricity can save or improve lives:
- Cardioversion – this is a medical term meaning to convert the heart rhythm (with the intent of converting it back to a normal (sinus) rhythm. This is a life-saving procedure that can be performed in a hospital or by an ambulance crew, or anywhere an AED (Automated External Defibrillator) is present. The AED is particularly good at saving lives, as many large public places now keep one around. In the event of a heart attack or other heart arrhythmia (abnormal rhythm of beats), there is a 3-5 minute window during which use of an AED gives a very good chance of survival without brain injury. Every minute after that window, the risk of brain injury increases and the chance of survival decreases. Effective CPR can extend this window slightly. The “dosage” of electricity varies by age, but in adults the usual dose is 300 joules or less. In order to direct current across the heart, the two pads that deliver a shock are placed in the upper right chest and below the heart on the left lower chest. Metal jewelry on the chest can interfere with and divert this path, making the shocks ineffective and causing skin burns. The reason people shout “clear” or “stand clear” before delivering a shock is because if someone is touching the victim/patient, it could also divert the current and cause a second victim and an uncorrected heart.
Pet Peeve Alert:
Hollywood tends to screw this one up. If the rhythm is flat-line with the high-pitched alarm noise, also known as asystole (Ay-sis-tuh-lee), the heart cannot be shocked back into action. In that situation in a real “code” or hospital emergency, medications like epinephrine would be used in an attempt to restart the heart to some other rhythm prior to shocking.
- Pacemakers – a pacemaker is a small machine about an 1/2-1 inch thick and a couple of inches in diameter. It is implanted into the chest of a person who has frequent arrhythmia. The most common arrhythmia treated with pacemaker is bradycardia, or very slow heart rate (less than 50 beats a minute). In some cases, when a too-fast arrhythmia can’t be controlled with medication, a surgeon will do a procedure called “ablation” which destroys the portion of the heart that is emitting the inappropriate signals, and then implant a pacemaker to take over the job. Ablation therapy often has to be repeated after a period of time, because unless the node (electrical generator in the heart) is completely destroyed, there is a chance of it becoming more active over time or regenerating. Pacemakers also require frequent monitoring, adjustment, and reprogramming, and must be replaced on a regular basis about every 5-7 years.
- ECT or electroconvulsive therapy – this treatment has gotten a bad rap over the years. ECT uses a much smaller dose of electricity (maximum 100 joules) and passes it directly across the brain. Modern ECT is done under careful observation and sedation, and is used to treat various psychiatric disorders that are not amenable to treatment with medications, including severe depression. ECT intentionally causes a grand mal seizure, which is a large part of it’s bad reputation. Grand mal seizures can be disturbing to watch. Here’s a video (warning, graphic). The purpose of ECT is similar to the purpose of cardioversion – to restart something that is misfiring, in this case, the brain. ECT remains somewhat controversial.
- Implanted electrodes – these electrodes monitor the electrical activity in the brain. Used in the treatment of intractable seizures (which cannot be controlled via medication alone). They are implanted in specific brain structures and left in while the person is carefully monitored for seizure activity. This guides later surgery to remove the misfiring portion of the brain. Surgeries of this nature vary in their success rates according to the type of procedure, but most patients experience relief from seizures.
As with many life saving techniques, cardioversion and ECT can cause more harm than good if performed on an individual who does not need them. Cardioversion can create an abnormal rhythm in someone whose heart is working fine. ECT can alter brainwaves and thinking patterns in someone whether or not suffering from depression or other psychiatric problems. Modern use of therapeutic electrical shock is accompanied by sedation and pain relief medications, except in cases of life-threatening emergency when there is inadequate time to sedate. Electricity can also cause severe burns, muscle damage, and extreme pain if performed incorrectly or if the path of electricity is not directed properly through one of the electrical structures of the body (brain and heart being the big two). Thus, electrical shocks have been the basis for torture and execution since shortly after the invention of man-made electricity.