The Federal Trade Commission will attempt to block the planned merger between Inova Health System, Northern Virginia's largest hospital chain, and Manassas, VA-based Prince William Hospital. Inova has been trying to add to its network of five hospitals in the region for almost two years, and the merger was expected to be completed later this month. The FTC argues that the merger between the competing healthcare providers would violate federal antitrust laws and lead to increased costs and reduced coverage for Northern Virginians.