Cybercardiologist!

• The pumping action of first the atria and then the ventricles of the heart is caused by a large electrical wave which travels inside the heart's muscular walls.
• It is possible for the normal pattern of this wave to be disrupted.
• When this happens, the heart beats irregularly, and often beats very rapidly. This is a life-threatening situation.
• These abnormal electrical waves often occur during, or as the result of, a heart attack. They kill 300,000 people each year in the United States.
• One such abnormal wave is called a spiral wave, so called because the wave pattern often looks like a spiral.
• We can model spiral waves and other irregular wave patterns using the computer.
• The computer models help us to understand how abnormal waves behave.
• The computer models allow us to test different ideas on how to stop these dangerous waves. The model on this Web page lets you apply an electrical shock anywhere and anytime you want. Drag your mouse across some portion of the simulated region to apply the shock. Watch how the waves are affected. Can you stop them?
• We can learn a lot by observing which ideas work and which don't. We use what we learn to devise drug therapies and design various electrical devices. We hope these new treatments will prevent these dangerous cardiac events, and help patients survive them when they occur.

More details, plus some more things to try with this simulation.
Program structure of this Java applet.