LITTLETON, Colo.--(BUSINESS WIRE)--Zynex, Inc. (OTCBB: ZYXI), a provider of pain management systems and electrotherapy products for medical patients with functional disability, announces that Zynex, Inc. and its subsidiary, Zynex Medical, have entered into a letter agreement with Marquette Healthcare Finance in which Marquette states its willingness to waive breaches of financial covenants by Zynex, Inc. and Zynex Medical.