Heart's helical band motion studied

PASADENA, Calif., -- U.S. scientists say they've created, for the first time, images of the heart's muscular layer and the link between it and the way the heart contracts. Cali- fornia Institute of Technology researchers say their findings could help create a road map for future cardiac surgical techniques. The researchers showed the muscular band that wraps around the inner chambers of the heart in a helix is actually a sort of "twisting highway" along which each con- traction of the heart travels. "The heart twists to push blood out the same way you twist a wet towel to wring water out of it," said Professor Morteza Gharib, who led the study.
Using a new imaging technique pioneered by Han Wen and colleagues at the National Institutes of Health, Gharib and Abbas Nasiraei Moghaddam created some of the first dyn- amic images of normal myocardium -- the middle muscular layer of the heart wall -- in action at the tissue level.
"We tagged and traced small tissue elements in the heart, and looked at them in space, so we could see how they moved when the heart contracts," Gharib said. "In this way, we were able to see where the maximum physical contraction occurs in the heart and when, and to show that it follows this intriguing helical loop." The research appeared in the December issue of Heart and Circulatory Physiology.

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