In almost every episode of the drama of the TV hospital ER , doctors rushed to a stretcher, shouting "VFib! . "and slapped electric paddles on the chest of a patient It is a drama that happens too often in real life as well: the heart of a patient, damaged by a blocked artery, stops its regular beating and begins fibrillating - . convulsion without pump blood But a study in the current issue of Journal of Clinical Investigation suggests that this type of heart attack called ventricular fibrillation could be expected and perhaps even avoided the key.: control of the electrical activity of the heart for signs of mathematical models known as chaos
the steady beat of a normal heart result from waves of electrical activity that tell muscle cells to contract .. generally, the wave begins at heart and stops at the top. But in a damaged heart, sometimes the wave spiral back into the muscle, where it is broken down into many small waves that disrupt the heart. "He squirmed as the surface of the boiling water," said Alan Garfinkel, a cardiologist at the University of California, Los Angeles, "and you're in trouble."
These seizures seem so disorganized that cardiologists have traditionally dismissed them as random. But in the early 1980s, researchers began to find chaotic behavior indices in isolated heart cells. Now Garfinkel and his team have seen the chaos wracking whole heart. implanted the reseachers electrodes in a dog's heart and diseased human hearts that had been removed from heart transplant recipients. to get a clearer signal, they slipped catheters with electrodes in the heart of the five patients with fatal arrhythmia called less atrial fibrillation. "It is like recording the orchestra inside the pit, rather than having your ear to the building wall," says Garfinkel
what he and his registered colleagues was a signature of chaos :. Behavior that is essentially unpredictable, but in the simple, random difference can be described by simple equations. "There is order in the disorder," said Garfinkel. Richard Verrier, a cardiac physiologist at Harvard Medical School, agrees, calling the work "the strongest case yet" that chaos plays a role in sudden heart attacks.
What more just before dissolving into chaos, signals, electrical heart to go through a "stage prechaotic" recognizable last up to a few minutes in which voltage spikes on the electrogram to begin deviate from their normal periodicity. "That's the amazing thing, he really knocked us," said Garfinkel. These models, he said, could possibly provide a warning signal for the onset of ventricular fibrillation. They could also accelerate the development of pacemakers smarter, could recognize that fibrillation is probable and nudge heart back into line.
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