System architecture: a compact, pulsatile artificial heart
The current development architecture combines a pulsatile chamber for the systemic circulation with a smaller pulse chamber and a continuous-flow pump for the pulmonary circulation. What is new is the combination as an overall system. Dimensions and values are under development and are given here only as a direction.
Non-clinical / benchtop research. Not an approved medical device.
Direction
Where development is heading — each with a status
None of these points is validated yet.
| Topic | Direction | Status |
|---|---|---|
| Output range | from rest to physical exertion, with reserve | Design target |
| Systemic pressure | reserve for exertion peaks, pressure only when needed | Design target |
| Pulmonary pressure | low pressure, limited and controlled | Design target |
| Size and shape | oriented on the human heart; fits the pericardium of the large majority of adults | Design target |
| Paediatric variant | smaller model with lower output | Planned |
| Membrane | several hundred million load cycles | Design target |
| Implantability | battery, electronics and energy transfer outside the pericardium | Current architecture |
Module 1
Chamber for the systemic circulation
The systemic chamber provides the pulsatile output into the systemic circulation. The membrane keeps blood space and drive separate; no shaft or piston seal through the blood space is planned. Volume and geometry are studied in variants.
Drive research is described on the Drive page; the membrane is the subject of membrane research.
Module 2
Pulmonary support: pulse chamber plus continuous flow
The pulmonary circulation works at much lower pressure. Two elements therefore share the task:
- Pulse chamber — maintains a pulsatile share in the pulmonary circulation.
- Continuous-flow pump — provides the base flow at low pressure; it runs permanently and is controlled.
Different size ratios of the chambers are being studied. Which pulsatile share is useful remains an open research question — see open research questions.
Module 3
Valves
Each chamber needs an inlet and an outlet — at least four valve functions in the two-chamber model. Biological and mechanical valves have been discussed as options; no specific valve platform has been selected yet. Reusing the patient's own valves is not a fixed design feature.
Materials
Materials under investigation
| Component | Candidates | Status |
|---|---|---|
| Housing, highly loaded structures | Ti-6Al-4V | Under investigation |
| Technical and insulating parts | PEEK | Under investigation |
| Membrane / elastomer | PU, PCU, BPU, silicone, EPDM — as a multilayer membrane | Under investigation |
| Housing wall | thin-walled titanium, locally reinforced at load paths and connection zones | Under investigation |
Energy
Energy supply
Battery, charging electronics and control are implanted outside the pericardium — space there is tight, a few centimetres of cable are not critical.
| Component | Concept | Status |
|---|---|---|
| Energy transfer | transcutaneous (TET), designed redundantly | Under investigation |
| Energy storage | implanted battery with reserve | Under investigation |
| Emergency power | separate connection | Under investigation |
| Power demand | being recalculated for the current architecture | Open |
Sensing
Sensing and control
Pressure and flow signals at several points are meant to adapt output, filling and pulmonary base flow to demand:
- Pressure: venous return, pulmonary circulation before and after the pump, chambers, systemic circulation
- Flow: venous return, pulmonary circulation, systemic circulation
The flows of both circulations are balanced against each other over several beats instead of reacting to every single beat. How sensor contradictions are to be detected is described under Safety & redundancy.