Spiral Waves Break Hearts
Cardiac cells, when grown as a sheet of tissue, often exhibit spiral
waves of electrical activity after two days in culture (see movie).
Such spiral waves, which have been associated with abnormal rhythms
in human hearts, may be a precursor to fatal cardiac rhythms such
as ventricular fibrillation.
Blocking communication between the cardiac cells with a drug called heptanol causes the spiral waves to break up into even more troublesome smaller spirals. Spiral wave breakup is believed to be a cause of ventricular fibrillation in human hearts(see movie).
A simulation closely reproduces the results of the above heptanol
The model consists of cells irregularly distributed in space which
are coupled to neighboring cells depending on their distance from
each other. The movie shows the effect of reducing the size of
the neighborhood of cell-cell interaction. For large neighborhoods,
the wavefront is smooth. For small neighborhoods, the wavefront
breaks into many small spiral waves.
(Thanks to Gil Bub and colleagues for these visuals and
for help with the caption. Additional information at Gil
Bub's website and a Java
Reported by: Gil
Bub, Alvin Shrier, and Leon Glass, Physical Review Letters,
4 Feb 2002.
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