The Heart Under Trauma, and the Twin We're Building

Who we are

At Rallypoint One, we build fast, high-fidelity models for our clients’ toughest problems. These are physics-informed digital twins of living systems, grounded in real biology and engineered to run quickly on open scientific software. They’re designed for the moments when the human body is under the most stress.

Building them takes fluency across disciplines that rarely sit together: cardiac physiology, numerical methods, high-performance computing, and a clear read on the mission each model has to serve. It’s the combination Rallypoint One was built around, and it’s what we bring to problems like hemorrhagic shock, where the physiology is the hardest and the stakes are the highest.

What we’re building

What is hemorrhage?

Hemorrhage is severe, uncontrolled bleeding. Blood leaves the body’s circulation faster than it can be replaced. Lose enough of it, fast enough, and the heart no longer has the volume it needs to keep tissues alive.

It is the leading cause of preventable death on the battlefield, and it doesn’t stop there. Hemorrhage takes lives in car crashes, operating rooms, and childbirth, anywhere serious bleeding outpaces the body’s defenses. In the minutes after a severe injury, the heart is pushed into territory that ordinary clinical models were never built to describe: acidosis, low oxygen, hypothermia, and a nervous system straining to keep up. Understanding what happens in those minutes, and predicting it before it turns fatal, is one of the hardest open problems in critical care.

The Cardiac Digital Twin

That’s the problem we’re building it to take on. Our model of the heart is multi-scale and physics-based, built in Julia, an open language for high-performance scientific computing. It spans single-cell electrophysiology, tissue-level propagation, and whole-body circulation, and it’s designed to capture how the heart responds under trauma and hemorrhagic shock. It’s hard, fascinating work, exactly the class of problem our team was built to solve.

Every scale at once

The heart doesn’t fail at one scale, so we don’t model it at one scale. A shift in the chemistry around one cell can show up, seconds later, as a change in the pulse you can feel at the neck. The hardest window is the gap between injury and recovery, where the heart can be harmed as much by the return of blood flow as by its loss. A digital twin lets us hold all of that together, and follow it from one level to the next.

Built in the open

High-fidelity physiology is computationally demanding, and Julia’s scientific-computing tools let us write models that are both readable and fast, then run the heaviest pieces on GPUs. We work in the open, so that what we build becomes a capability the wider research community can use, not a black box that ends with one contract.

Come find us this August

From August 3–6, we’ll be at the Military Health System Research Symposium (MHSRS), the Defense Department’s premier military-medicine meeting, just outside Orlando, Florida.

In the weeks around the conference, we’ll publish a short series inspired by what we see there, digging into the reperfusion paradox, the idea of “blood failure,” keeping the heart alive on support, and the move from algorithms to digital twins. Each post will take a question raised at MHSRS and ask what our modeling has to say about it.

More soon, and if you’ll be at MHSRS, come find us!