It starts suddenly, without warning. Maybe a twinge, or a slow, steady pressure in your chest. At first, it's not quite painful, but the discomfort is there nonetheless. You break out in a cold sweat, as if someone has just walked over your grave.

You feel somewhat nervous now, trying to place the last time you felt like this. But you can't remember a time when you ever felt like this and why does your arm and neck hurt so much all of a sudden?

You have stopped whatever it is you're doing, because whatever this is that's happening to you has grabbed your full attention. The pressure in your chest is still building, and you're breathing like you've just run the marathon. Your brain is spinning, trying to make sense of the signals that are coming from your body. Then, with a wave of nausea, you realize that everything is spinning.

Your spouse (co-worker, friend, neighbor in line) looks at you in alarm, calling your name. But they sound like they're in a tunnel far away. You are caught, paralyzed between waves of fear, flight, and (now) absolutely excrutiating pain.

"Oh my God," you hear someone say, "I think he's having--"

A heart attack.

That's what you would have heard had you remained conscious for the rest of this unexpected event. But your brain has mercifully shut down for the time being, as all conscious thought becomes a secondary matter as your body fights itself to make things normal again.

There are many types of cardiac events, some as sudden and painful as this one, others more subtle and vague. There are many causes of a heart attack, too: arterial blockage, clotting, and arrhythmia are just some that can affect the human heart.

Arrhythmia is any condition where the heart begins to lose its normal rhythm. Arrhythmia can be anything from a tiny heart flutter to a full-blown fibrillation--a condition where the heart can begin beating up to 600 times a minute. This latter condition can be likened to overclocking of the heart, where the normal timekeeper of a heart's rhythm is suddenly (and very mistakenly) joined by other sections of the heart, each competing with the other sections to take over the heart's rhythmic pattern--but leaving an end result of a cacophony of beats.

Fibrillation is a very serious condition, but even here there is a matter of degrees: a common form of fibrillation is atrial fibrillation (AF), a condition that effects around 2 million people in the United States. AF is not usually regarded as especially life-threatening--the brief periods of signal misfires can cause discomfort, but typically are not fatal. (Over time, however, AF can ultimately lead to heart tissue damage and even strokes.)

Not so ventricular fibrillation, where the misfires are so strong and so erratic, the heart quickly loses the ability to pump blood. VF, or "v fib" as the doctors in the ER call it, is just about the end of the line for the heart, unless it can be stopped with defibrillation. "Zapping" the heart with a strong electrical field can sometimes "reset" the timekeeper of the heart (a cluster of cells known as the sinoatrial (S-A) node) and get things back to a normal, sinus rhythm.

Or then again, maybe it won't, because no one really knows the true mechanics of why defibrillators work.

Still, defibrillators are a very important tool in combatting the massive damage a v fib event can do--as are several medicines that might soothe the heart tissue back into a more regular mode. But these are treating the symptoms of fibrillation. Whether it's AF or VF, doctors and scientists are still struggling to find out why fibrillation happens in the first place.

Today, right now, research is taking place to learn just what triggers a fibrillation, with the hope that perhaps such events can be shut down before they even get started.

One such research program is taking place at the University of Alabama, Birmingham (UAB), where the effects of electrical fields on human heart tissue are observed not in a gory lab, but rather in the confines of a Beowulf cluster of servers running Linux.

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