'A Lego kit for healthcare builders': Jonathan Bush launches Zus with medical records in mind

Jonathan Bush is back for another act. On Thursday, the founder and former chief executive officer of medical IT giant athenahealth launched a new startup called Zus. The company, which debuted with $34 million in a funding round led by Andreessen Horowitz with participation from Rock Health and other venture firms, wants to become the common layer digital health companies use to build their tools, view health records, and ultimately treat patients.