A few days ago, I sat in a medical recliner at the University of California, San Francisco. A cardiologist placed 10 stickerlike electrodes onto my limbs and chest and then connected the wires to a dated-looking contraption with a screen and a keyboard on a cart.
About a minute later, a printer produced a chart of my heart’s electrical activity on red graph paper. The procedure I had undergone was an electrocardiogram, or an EKG, which is used to diagnose cardiac problems like arrhythmia and heart attacks.
