Heidi Health raises $340 million for clinical AI agents

Heidi Health's pitch is shaped by a paradox in clinical AI adoption. The American Medical Association's survey found 81% of physicians in 2026 said they were using augmented artificial intelligence — more than double a 2023 poll — yet AMA CEO John Whyte cautioned that physicians remain wary of AI taking on tasks requiring clinical judgment, and worry it could degrade human specialists' expertise if substituted for it. Heidi's answer is to position its platform as augmentation: Scribe records patient history and symptoms ambiently, while Evidence pulls trusted medical research into the point of care with in-line citations and risk scoring. The company said Evidence has answered more than 10 million queries since its March launch.

The funding structure itself is notable. Rather than a single round, Heidi combined a $100 million Series C led by Blackbird with $240 million in growth investment from General Catalyst — capital aimed explicitly at deepening adoption inside health systems rather than simply building the product. That mirrors the traction the company cites: an enterprise activation rate around 62% across major public and private health systems since its October Series B, use by Beth Israel Lahey Health in Massachusetts, and selection as sole supplier for NHS England Midlands, which Heidi describes as the largest clinical AI procurement in NHS history.

What the outcome hinges on is whether that activation rate translates into durable, system-wide deployments rather than pilot programs, and whether clinicians' stated caution about AI overreach is eased by tools that stay clearly on the administrative side. That question matters most to the health-system procurement and clinical-informatics teams now weighing AI agents against incumbent documentation vendors, and to Heidi's investors, who have placed a substantial bet that hospital-scale adoption, not individual clinician sign-ups, is where the market settles.