Design of an anatomically accurate, multi-material, patient-specific cardiac simulator with sensing and controls

We present the design, development and fabrication of an anatomically accurate, inhomogeneous, elastomeric cardiac model for in vitro testing of cardiac devices. Segmentation of clinical data was performed with Mimics software (Materialise). Mold creation and optimization was performed in 3-Matics (Materialise) using the tooling module. A total of twenty-one molds were designed including sixteen two-part molds (cardiac chamber internal volumes and endocardial walls, main vessel internal volumes and outer walls), four one-part molds for the valve annuli and one two-part mold for final myocardium cast. Molds were optimized for alignment and degassing in 3-matics and then 3-D printed (Objet Connex 500). Internal volumes were cast with paraffin wax. Endocardial and vessel walls and annuli were subsequently cast in elastomeric materials that matched material properties of corresponding native tissue. Internal volumes were then melted out, and internal structures were sutured together, separated by functioning valves created using an involuted tube surgical technique. Finally, these internal structures were aligned in an outer mold and a final elastomeric layer was cast to representing the myocardium. We describe the subsequent attachment and passive actuation of this synthetic model using a modification of a commercially available pump, so that heart rate and systolic and diastolic volumes can be user-modified, and sensing capabilities can be incorporated and controlled through a general user interface. The final design is a patient specific, easily modifiable synthetic benchtop model that can be used to provide meaningful data on the design of cardiac devices before moving to pre-clinical testing. Figure 1: Workflow for creation of anatomically accurate, inhomogeneous elastomeric cardiac model