60 Defibrillators in One Room

Today I, along with several other engineers from my office, went to Swedish Hospital in Seattle to attend a support group meeting for people with implantable cardioverter-defibrillators (ICDs as we like to call them) implanted in their chests. These are mostly people who have had heart attacks and whose hearts are subject to ventricular fibrillation which is generally lethal, and/or tachycardia which is not always lethal but is a very unhealthy state for the heart to be in. Both conditions are treated with a rather large electric jolt that resets the cardiac cells to a common electrical state and recalls the heart to its duty.
There were about 60 patients in attendance and we were there to make a short presentation on the history of ICDs, the basics of how they work, and a description of the development process. Then we took questions.
One patient, a retired engineer natch, wanted a list of all the parameters available for tweaking the behavior of his ICD. We referred him to his cardiologist. Another wanted to know why, if we build all these options into the devices, does his doctor just use the nominal values and never change them. Once again, a question for his doctor who is likely too busy (or lazy?) to find out what capabilities are available.
The most interesting question was this: why don't the devices generate some kind of warning so the patient knows he/she is about to be shocked? In fact, our devices do emit a high frequency tone followed by beeps just before the zap. However, most patients are elderly and many probably can't even hear that frequency. Also the volume is diminished since there is about an inch of flesh between the device and the outside world. We need to think about this. Interestingly, as engineers we don't get much feedback from patients. Most comes from doctors who probably don't consider this as much of an issue. But if you're driving down the freeway and get a jolt due to tachycardia, you will be incapacitated for several seconds. It seems like common sense to be warned so you can pull over ahead of time. Hmm...
It was quite amazing to be in an auditorium full of people who would be dead without the technology that I work on every day. It sort of adds meaning to our day-to-day activities you might say. Hassling with recalcitrant underlings, schedule pressures, controlling behavior on the part of certain clueless managers, and the always challenging technical work itself look quite different when you realize in a very visceral way that lives are saved by what we do.