(Corrects headline to indicate Nautilus loss was tossed out)
WASHINGTON, June 2 (Reuters) - The U.S. Supreme Court on Monday threw out a lower court decision in a patent fight over heart rate monitors, a decision that will affect other patent infringement fights.
Biosig Instruments Inc had accused Nautilus Inc of infringing on its patented technology for monitors built into fitness machines like treadmills, which register electrical waves to estimate a user's heart rate.
Far beyond the gym, the case has implications for the ongoing dispute over "patent trolls," the derisive name given to companies that sue for infringement, or attempt to extract licensing fees, by using what critics say are weak or overly broad patents.
The Supreme Court said the U.S. Court of Appeals for the Federal Circuit had set the bar too low in allowing patents to be written vaguely.
"The expressions 'insolubly ambiguous' and 'amenable to construction,' which permeate the Federal Circuit's recent decisions ... fall short ... and can leave courts and the patent bar at sea without a reliable compass," the Supreme Court said in its ruling.
The case at the Supreme Court is Nautilus v Biosig Instruments, Inc and is No. 13-369. (Reporting by Diane Bartz, editing by Ros Krasny and Doina Chiacu)