"The technical and clinical challenges were too daunting, " says Thomas Burnett, Thoratec's chief operating officer.

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Leaders in heart replacement technology, such as Thermo Cardiosystems and Thoratec Laboratories have long shied away from making a permanent artificial heart.

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HeartWare rose on an analysis presented at the annual meeting of the American Heart Association that showed its device for helping the hearts of transplant patients pump may outperform that of rival Thoratec, which was one of the biggest decliners.

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