Register for an account


Enter your name and email address below.

Your email address is used to log in and will not be shared or sold. Read our privacy policy.


Website access code

Enter your access code into the form field below.

If you are a Zinio, Nook, Kindle, Apple, or Google Play subscriber, you can enter your website access code to gain subscriber access. Your website access code is located in the upper right corner of the Table of Contents page of your digital edition.


A Digital Heart


Sign up for our email newsletter for the latest science news

What happens to the heart during a heart attack? To better understand a heart in extremis, two medical researchers have made a three- dimensional model of the electrical activity in a dog’s heart. (Dog hearts have been extensively dissected and probed, so researchers know much more about canine hearts than they do about human hearts.) In a normal heart (above), the electrical activity (shown in blue) sweeps across cardiac muscles in one quick wave. But during a heart attack, the electrical excitation spreads randomly through the heart, shown in the lower image as a splotchy muddle of relaxed (red) and excited cells. This chaotic activity reverberates all over the surface and within the heart. As a result, the heart no longer pumps blood, because it doesn’t contract and expand systematically, says Raimond Winslow, a biomedical engineer at Johns Hopkins who developed the model with Denis Noble of Oxford. The waves just circulate in a chaotic fashion within the heart, Winslow says. This model is just the first of a full range of simulations that he hopes researchers will be able to use to develop better drugs and pacemakers.

    2 Free Articles Left

    Want it all? Get unlimited access when you subscribe.


    Already a subscriber? Register or Log In

    Want unlimited access?

    Subscribe today and save 70%


    Already a subscriber? Register or Log In