Coupling reduced-order blood flow and cardiac models through energy-consistent strategies: modeling and discretization

In this work we provide a novel energy-consistent formulation for the classical 1D formulation of blood flow in an arterial segment. The resulting reformulation is shown to be suitable for the coupling with a lumped (0D) model of the heart that incorporates a reduced formulation of the actin-myosin interaction. The coupling being consistent with energy balances, we provide a complete heart-circulation model compatible with thermodynamics hence stable numerically and informative physiologically. These latter two properties are verified by numerical experiments.

3D bioprinted and integrated platforms for cardiac tissue modeling and drug testing

Recent advances in biofabrication techniques, including 3D bioprinting, have allowed for the fabrication of cardiac models that are similar to the human heart in terms of their structure (e.g., volumetric scale and anatomy) and function (e.g., contractile and electrical properties). The importance of developing techniques for assessing the characteristics of 3D cardiac substitutes in real time without damaging their structures has also been emphasized. In particular, the heart has two primary mechanisms for transporting blood through the body: contractility and an electrical system based on intra and extracellular calcium ion exchange. This review introduces recent trends in 3D bioprinted cardiac tissues and the measurement of their structural, contractile, and electrical properties in real time. Cardiac models have also been regarded as alternatives to animal models as drug-testing platforms. Thus, perspectives on the convergence of 3D bioprinted cardiac tissues and their assessment for use in drug development are also presented.

Utility of 3D printing of left atrial appendages for closure with Watchman Devices and comparison of computed tomography and transesophageal echocardiography based models

Three dimensional (3D) printed cardiac models are useful for WATCHMAN device procedural planning, sizing, and complication reduction. These models also provide accurate representation of dynamic heart anatomy, helping practitioners determine their procedural approach and select proper device sizing. While the efficacy of 3D models obtained from Computed Tomography and Transesophageal Echocardiography over 2D Transesophageal Echocardiography imaging for WATCHMAN procedural planning has been demonstrated, this project aims to directly compare 3D Computed Tomography versus 3D Transesophageal Echocardiography and determine which is more favorable. Computed Tomography and Transesophageal Echocardiography 2D imaging studies from patients that underwent LAA WATCHMAN closure device implantation we used as templates for 3D cardiac models. These 3D models were scored using a 10-point Likert questionnaire. Scoring was conducted by a diverse team that included cardiologists, research specialists, medical students, and 3D printing technicians. Three dimensional models developed using Computed Tomography demonstrated favorability over 3D models by all qualitative measures. Scoring indicates that Computed Tomography based 3D models are superior tools for WATCHMAN sizing, multi-level medical education, and physician preparedness. To our knowledge, this is the only study that compares 3D models crafted from each imaging modality, and we hope that it encourages future use of 3D modeling techniques based on Computed Tomography scans.