US Supreme Court agrees to hear Nautilus heart monitor case

On January 10, the US Supreme Court agreed to decide on so-called ambiguous patent claims in Nautilus v Biosig Instruments.

Nautilus petitioned the court to decide whether the Federal Circuit was right to accept that “ambiguous patent claims with multiple reasonable interpretations—so long as the ambiguity is not ‘insoluble’ by a court—defeats the statutory requirement of particular and distinct patent claiming”.

The case concerns a claim related to Biosig’s US patent 5,337,753, which covers a heart rate monitor for use with an exercise apparatus.

According to the claims, the monitor eliminates signals given off by skeletal muscles made when users move their arms or squeeze the monitor with their fingers. The invention claims pairs of electrodes that are mounted in a “spaced relationship” with each other.

The district court ruled the claims were indefinite because it is ambiguous what the “spaced relationship” implies. However, the Federal Circuit found the claim language provided “sufficient clarity”.

Biosig brought the initial patent infringement against Nautilus at the US District Court for the Southern District of New York, where it argued the exercise equipment company infringed claims 1 and 11 of the ‘753 patent.

Nautilus then filed a motion for summary judgment seeking to have the ‘753 patent invalidated for indefiniteness, which the district court granted. Biosig successfully appealed against the decision at the Federal Circuit in April 2013.

Circuit Judge Wallach wrote in the decision: “A claim is indefinite only when it is ‘not amenable to construction’ or ‘insolubly ambiguous’”.