The Amateur Scientist: Home is Where the ECG Is; June 2000; Scientific American Magazine; by Carlson; 3 Page(s)

I have never been so terrified as the day I thought I was going to lose my wife. I blew through all the red lights on our way to the hospital, as Michelle rapidly grew weaker in the passenger seat. It all started just 10 minutes earlier when I confirmed with my homemade electronic stethoscope (see the October 1997 column) that her heart was beating abnormally. By the time we barreled into the hospital parking lot, she could hardly speak at all. I had to carry her into the emergency room.

It turned out to be an easily treated side effect of a prescription steroid she was taking. We were home in six hours. But the experience scared me so much that I built Michelle an automated heart-monitoring device to give us more warning should the symptoms ever reappear. That monitor was acoustical. Although such a sensor makes it easy to detect an irregular rhythm, you can learn much more by recording the heart's electrical signature. So I decided to upgrade to an electrocardiograph, or ECG (also abbreviated EKG). It can be built in an afternoon for about $60.