Reinstated a medical device seller's claim that certain Blue Cross Blue Shield health insurance companies violated antitrust law by unreasonably restraining trade in the national market for outpatient cardiac monitors. The seller of a cardiac monitoring device contended that it was shut out of the market because the defendants conspired to deny insurance coverage for its product to shield themselves from patient demand for it. Holding that the seller stated a claim under section 1 of the Sherman Act, the Third Circuit reversed dismissal of the complaint and remanded for further proceedings.