Inspired by this news tidbit in which a woman in China is claimed to have been electrocuted by her iPhone (she answered a call while it was plugged into the charger).
Assuming there are no actual burn marks, then death would have been caused by electrical current passing through her brain and/or heart. Can an autopsy reveal definitive signs of this?
An autopsy would mainly be helpful to exclude causes of death; in the absence of burns and no evidence of any electrical malfunction of the device9s), this would be very difficult to establish.
But maybe the autopsy will turn up incontrovertible signs of sudden cellphone-induced brain cancer death. :dubious:
An electrical current passing through a body can directly injure tissue; both skin and internal parts. Internally, the electrical current can burn your parts and coagulate your soft tissue. This physical injury can be profound enough to be found at autopsy.
However, it is also possible for the current to be strong enough to disrupt a normal heart rhythm and precipitate a fatal arrhythmia (typically, ventricular fibrillation but also cardiac standstill that is prolonged enough to cause death) without leaving a physical trace for Jackmanii and his pards to see. In that case the autopsy would be useful only for exclusion.
I believe it is the case that household alternating current is considered more dangerous than direct current for precipitating malignant arrythmias, and in fact cardiac standstill from application of direct current is usually followed by a spontaneous recovery of a normal rhythm. In fact, of course, that’s why we use DC defibrillators for a variety of malignant arrhythmias.
For a current that doesn’t fry you inside, it’s the heart and not the brain that would lead to the lethal event. Just buzzing the brain might make you loopy or unconscious, but I can’t think of a mechanism short of tissue destruction where it would kill you the way a lethal arrhythmia will. Might even help your depression…
I used to have a friend (he has since passed) who was involved in research into some of the early pacemakers. According to him, we just about could not have picked a worse frequency for AC power systems from a safety point of view. Frequencies right around 50 to 60 Hz (used throughout the world) are about the best you’ll get if you want to use them to stop a heart from beating. They used to use 60 Hz AC to stop animal hearts (put them into fibrillation) so that they could then test their pacemaker’s ability to restart a normal rhythm.
I am an engineer, not a medical doctor, but here is my understanding of it. Currents of about 5 mA and below are generally considered “safe” and aren’t likely to cause arrhythmia. As the current increases, the chance of arrythmia increases, with AC being more likely to cause a problem than DC. Eventually, though, the risk of death actually decreases. Instead of going into arrhythmia, the heart muscles just all clamp. Of course, the heart isn’t pumping blood at that point so if the source of the current isn’t removed the victim is going to die. But as I understand it, if the current is removed, the heart will generally go back into a normal rhythm on its own at that point. At even higher levels of current, though, burn damage starts to occur and the chance of death again increases.
Getting electrocuted by answering a cell phone while it is on the charger is a common urban legend, especially in that region of the world (it’s like the Korean fan death myth in that respect). I suspect that the woman simply had a heart attack or stroke or some other type of death at approximately the same time as she answered the phone. Someone saw the phone in her hand and immediately blamed it on the “known” cause of electrocution.
An iphone charger is too low in voltage to overcome skin resistance and result in a lethal level of current. You really need to get above 50 volts or so before the voltage becomes dangerous. You can grab both terminals of a car battery and not get shocked. You would have to have some fault at the outlet that would allow the supply voltage to travel up the cord to the phone. I suppose it’s possible that it’s a knock-off charger and they grounded the charger return to the AC ground, and the outlet was either ungrounded or was miswired to put 220 on the “ground” or “neutral” connection.
Whether or not the phone was ringing at the time wouldn’t matter with respect to any possible hazardous condition, but in these myths the shock only occurs when the person answers a ringing phone, at least in the versions that I have heard.
might there be some truth to that in the case of wired phones/POTS? ISTR the line can have 90-100 volts on it when ringing the phone.
Ring voltage is typically about 90 volts at 20 Hz, though it can vary a bit. The current is kinda limited though. You’re not going to get more than a few hundred milliamps out of it at best. Hook up enough phones (typically about 4 or 5) and they won’t ring because there isn’t enough current there to power them all. Theoretically the line could supply enough current while ringing to possibly throw your heart into arrhythmia, if just barely.
You’d have to have frayed wires or some other fault in the phone that would allow you to touch the bare wires, and you’d have to touch one wire with one hand and the other wire with the other hand in order to get the flow of current to go through your chest. I suppose if you had picked up the phone and happened to be switching it from one hand to the other at exactly the moment it rang and you had frayed wires and just happened to touch them in the right way it might be possible. It’s not very likely to result in anything more than discomfort though.
You’d probably also need to have wet hands to get enough current flowing through the skin to overcome the skin’s natural resistance.
Interesting post. Thanks.
From a medical defibrillator standpoint, we typically increase the current as needed until we get an effect, unless the patient is in a lot of trouble to begin with. Then we start with a higher current. The purpose of increasing the current is mostly to overcome resistance through the skin (we use conduction pads to help as well). The idea is to get an effect with the least current to avoid secondary electrical trauma.
From a “safe” standpoint, timing is important as well if the patient has an organized rhythm. A countershock delivered at the wrong point in the electrical cycle of the heart can precipitate ventricular fibrillation. If the patient is already in V fib, or some other very poorly organized rhythm, synchronizing the countershock to the electrical cycle is not necessary (and usually not even possible for very chaotic rhythms).
When the chest is open and the heart is directly accessible (or when internal wires are geing used), much less current is required, obviously.
