UPDATE: World Heart To Refine Heart Pump, Halts Study Enrollment

   (Updates with more detail and fresh share price) 

World Heart Corp. (WHRT) said it has paused enrollment in a study of its Levacor heart pump, pending regulatory approval of refinements to the device.

Shares dropped 11% to $1.65 in recent trading. The stock has plunged about 72% over the past year.

The pump uses magnetic levitation to suspend the spinning impeller, its only moving part, where others use blood or mechanical bearings. The company says that's expected to provide improved blood compatibility. World Heart has been unprofitable as it is focused on development of the device.

The company said Wednesday design modifications will be "technically ready in the next two to three months," but the timeline for their implementation depends on approval by the U.S. Food and Drug Administration, the timing of which is uncertain. Device makers face the possibility of further inquiry by the agency in such reviews, which can lead to delays.

World Heart said last month it planned to make the refinements to the device, and that enrollments would continue to be slow in the study until they were completed.

 
   -By Matt Jarzemsky, Dow Jones Newswires; 212-416-2240; [e-mail]