---
title: "Pneumatic artificial muscle–driven left ventricular simulator developed using Interpretive Structu"
id: "plos-one-22-methodological-development-of-a-pneumatic-artificial-muscle-driven-left"
canonical_url: "https://medichelpline.com/clinical-feed/plos-one-22-methodological-development-of-a-pneumatic-artificial-muscle-driven-left"
content_type: "clinical_feed_article"
specialty: "Cardiology"
source_name: "PLOS ONE (Medicine)"
source_url: "https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0355859"
published_at: "2026-08-13T14:00:00.000Z"
evidence_level: "Journal Feed"
license: "CC-BY-NC-4.0 / Informational Use"
---
# Pneumatic artificial muscle–driven left ventricular simulator developed using Interpretive Structu
## Provenance & Clinical Metadata
- **Canonical URL:** https://medichelpline.com/clinical-feed/plos-one-22-methodological-development-of-a-pneumatic-artificial-muscle-driven-left
- **Specialty:** [Cardiology](https://medichelpline.com/clinical-feed/cardiology.md)
- **Primary Source:** PLOS ONE (Medicine)
- **Source URL:** [Original Journal Publication](https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0355859)
- **Published At:** 2026-08-13T14:00:00.000Z
- **Evidence Rating:** Journal Feed
## Executive GIST (TL;DR)
- The study developed a bio-inspired, less complex left ventricular (LV) simulator driven by **pneumatic artificial muscles** embedded in a deformable latex ventricular wall. - Interpretive Structural Modeling (ISM) was applied as a systematic methodological framework to evaluate alternative LV actuation methods and materials and to identify hierarchical relationships among design parameters prior to prototyping. - ISM indicated that pneumatic artificial muscles coupled with latex rubber were the most suitable actuation-material combination for the LV simulator. - A prototype LV chamber with helically oriented artificial muscles was fabricated to reproduce twisting (torsion) and longitudinal shortening of the ventricle without complex electromechanical drivers or active feedback controllers. - Experimental evaluation included healthy and diseased conditions at heart rates of 50, 60, 70 and 80 beats per minute; the beating simulator produced average flow rates up to 2.25 L/min. - Cardio-mechanical motion was assessed: the simulator achieved 21 degrees of rotation at the apex (twisting) and 11 mm of apex shortening, demonstrating LV-like wall motion. - The platform aims to bridge conventional piston-driven mock circulatory systems and more complex soft-robotic models, offering lower fabrication and operational complexity while enabling physiological-like wall mechanics. - The prototype is presented as a promising preliminary testbed; the authors state further improvements are needed for the simulator to reach full human LV hemodynamic and mechanical performance. - Data supporting the study are reported within the manuscript and supporting information; no specific external funding was declared and no competing interests were reported.
## Clinical Analysis & Structured Key Points
Methodological development of a pneumatic artificial muscle-driven left ventricular simulator using interpretive structural modeling | PLOS One Browse Subject Areas ? Click through the PLOS taxonomy to find articles in your field. For more information about PLOS Subject Areas, click here . Article Authors Metrics Comments Media Coverage Reader Comments Figures Figures Abstract Mock circulation systems can replicate a wide range of cardiac operating scenarios, such as cardiovascular diseases, particularly muscular dysfunctions. These systems are operated by sophisticated control algorithms which require complex driver and data acquisition systems, whereas animal models raise ethical concerns. Therefore, there is a need for novel testbeds to overcome the challenges in the existing systems. The aim of this study is to develop a less complex and realistic left ventricular (LV) simulator. The Interpretive Structural Modeling (ISM) approach was utilized to evaluate different left ventricular actuation methods and materials. ISM revealed that the most suitable method to actuate the LV is using the pneumatic artificial muscles and latex rubber. The performance of the new LV simulator was evaluated for healthy and diseased conditions at 50, 60, 70 and 80 bpm heart rates. The experiments revealed that the beating LV simulator can generate average flow rates of up to 2.25 L/min. The actual human LV-like wall motion was also verified by the twisting angle on the apex of the beating LV simulator with 21 degrees of rotation and 11 mm of apex shortening. The prototyped beating LV simulator is a promising preliminary platform and may reach actual human LV’s hemodynamic and cardio-mechanical performance with further improvements. Citation: Baturalp TB, Bozkurt S (2026) Methodological development of a pneumatic artificial muscle-driven left ventricular simulator using interpretive structural modeling. PLoS One 21(8): e0355859. https://doi.org/10.1371/journal.pone.0355859 Editor: Francesco Visentin, University of Verona: Universita degli Studi di Verona, ITALY Received: January 6, 2026; Accepted: July 27, 2026; Published: August 13, 2026 Copyright: © 2026 Baturalp, Bozkurt. This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability: All relevant data are within the manuscript and its Supporting information files. Funding: The author(s) received no specific funding for this work. Competing interests: The authors have declared that no competing interests exist. Introduction Mock circulatory systems are hydraulic devices consisting of electromechanical components and simulate blood pressures and flow rates in the cardiovascular system [ 1 ]. They have been widely used in developing and testing cardiovascular implants, such as artificial heart valves and heart pumps, before marketing [ 2 ] as the international standard requires testing of the hydrodynamic performance of such implants [ 3 ]. Moreover, anatomical models can be installed on these devices to simulate patient-specific conditions [ 4 ]. Physiological cardiovascular signals are generated in mock circulatory systems in chambers representing ventricles and pressurized by pistons, which are controlled to follow a reference position as in the commercial Vivitro pulse duplicators [ 5 ] or pressure trajectories as described by Schampaert et al. [ 6 ]. Time-varying elastance functions or single-fiber contraction models have been used to simulate reference trajectories in the mock circulatory systems being controlled to follow pressure signals [ 7 , 8 ]. The ventricular chambers in these systems can be silicone sacks [ 5 ] or can be made of rigid materials [ 8 ]. Nonetheless, ventricular volumes are simulated by the stroke of the pistons over each cardiac cycle and measured by tracking the piston motion [ 5 , 8 ]. The aortic compliance and resistance are modeled by air chambers and throttle valves to simulate the aortic pressure and flow rates [ 9 ]. Although mock circulatory systems also allow the installation of ex-vivo components, such as cardiac valves and the evaluation of complex scenarios, such as papillary muscle repair [ 10 ], adding such components to these systems increases the complexity of the design and operating conditions [ 11 ]. Hybrid mock circulatory systems consist of an interface including a numerical model that simulates hemodynamic variables such as flow rate or volume and a physical section in which pressures are simulated [ 9 ]. An example of a hybrid mock circulatory system is presented by Ochsner et al. [ 12 ] and used to test ventricular assist devices. However, the design and development of hybrid mock circulatory systems present challenges such as fast and accurate numerical-physical interfaces or hardware drivers required to operate these devices [ 9 ]. Ex-vivo heart platforms offer realistic anatomical models to evaluate clinical scenarios and cardiac implants [ 13 , 14 ]. Active beating heart platforms include an explanted heart from animals, such as a porcine heart [ 15 ]. Explanted hearts are oxygenated, and electrical activity is restored; however, the heart rate is not regulated in these hearts due to a lack of the autonomic nervous system, and the natural rhythm of the heart might be remarkably different from physiological conditions [ 16 ]. Passive beating heart platforms again include explanted porcine hearts however, pressure and flow rate signals in these cardiac models are generated using pistons as in the mock circulatory systems [ 17 ]. Nonetheless, increasing ethical concerns about the use of animal models in research and established roadmaps to reduce animal experiments [ 18 ] may negatively affect the use of ex-vivo cardiac models. More recent studies suggest the use of flexible material and anatomical models to simulate left ventricular function. For instance, Rocchi et al. [ 19 ] tested a platform simulating patient-specific anatomy made of 3D-printed phantoms with a combined in silico lumped-parameter model to reproduce pressure–volume relations. A limitation of the patient-specific framework is its workflow complexity, as clinical image segmentation, geometric reconstruction, and customized fabrication may increase time, cost, and technical requirements and may limit scalability. Davies et al. [ 20 , 21 ] report a bioinspired soft robotic left ventricle simulator that uses thin-filament artificial muscles to mimic multilayered myocardial biomechanics, reproducing physiological pressure and volume profiles in both healthy and failure conditions within a mock circulation loop. Soft-robotic systems with fully synthetic valve simulators rely on artificial actuators and complex actuation mechanisms with data-driven controllers to reproduce the cardiac contraction [ 21 ]. Although this system provides a soft robotic model capable of simulating complex cardiac motion and valve interactions, the fabrication and experimental setup remain highly specialized and complex, potentially limiting rapid reproducibility and wider adoption in routine benchtop studies or clinical research environments. Beating heart simulators activated with artificial muscles offer possibilities to overcome the challenges in the aforementioned cardiac models [ 22 ]. Moreover, anatomical models can be molded and produced, whereas the use of artificial muscles can replicate cardiac contraction and relaxation over a cardiac cycle. However, designing a beating left ventricular (LV) simulator that replicates the geometry, wall motions, and muscle fiber orientations of a real human LV chamber is a complex problem [ 23 – 25 ]. This is because abnormal left ventricular wall motion is associated with health problems such as arterial hypertension, diabetes mellitus, coronary artery disease, and cardiac arrhythmia in elderly individuals [ 23 ], and may increase the risk of stroke recurrence [ 26 ]. Moreover, the shape of a healthy left ventricle resembles an ellipsoid, whereas it becomes more spherical in systolic heart failure, and myocardial fiber orientation is impaired [ 24 ]. Evaluation of clinical scenarios and different therapies for physiological conditions require realistic LV simulators. Therefore, design and operating factors in such simulators must be selected carefully to obtain realistic results. The novelty of the developed LV simulator is as follows. Methodologically, this study introduces Interpretive Structural Modeling (ISM) as a systematic framework for evaluating alternative ventricular actuation concepts and identifying the hierarchical relationships among design parameters prior to prototype development. Conceptually, the simulator shifts from the conventional piston-driven reproduction of ventricular hemodynamics toward a bio-inspired replication of myocardial mechanics, including ventricular torsion and longitudinal shortening. Technologically, the proposed platform integrates helically oriented pneumatic artificial muscles embedded within a deformable latex ventricular wall, enabling physiologically relevant twisting and contraction without the need for complex electromechanical drive systems, active feedback controllers, or highly specialized fabrication processes. Compared with existing mock circulatory systems and recent soft-robotic ventricular simulators, the proposed design aims to offer a relatively simple LV simulator with lower complexity. Materials and methods In this study, the ISM methodology proposed by Warfield [ 27 , 28 ] is used to deal with complex design issues of the beating LV simulator. ISM provides a fundamental understanding of how various design parameters (elements, variables, system components, etc.) relevant to a design problem are interrelated and thus helps researchers to structure them in a meaningful manner, develop collective intelligence, and overcome complex problems. The goal of ISM is to develop a relationship map that includes paths of ideas and threads of thought to transform unclear and poorly expressed models into a visible, well-defined, and relatively easily solvable model [ 29 ]. The ISM method was applied to three different beating LV simulator design approaches (pneumatic artificial muscle, flexible band, and artificial muscle actuation) to compare and analyze the interaction of factors and their effects on the performance of the LV simulator. The first step of the ISM procedure is to utilize the knowledge of experts in the field to build a model that represents a complex system. A literature survey was conducted to construct the knowledge of experts to build the ISM model for different design approaches for the beating LV simulators. The ISM framework used in this study was constructed through a structured synthesis of both literature-based knowledge and expert judgment. First, a comprehensive literature survey was conducted focusing on mock circulation loops, left ventricular simulators, cardiac biomechanics, and actuation technologies for biomimetic cardiac devices. Key design factors influencing ventricular simulator performance—such as geometric fidelity, wall motion characteristics, controllability, actuation efficiency, structural integrity, and integration with the circulatory loop—were identified from prior studies and compiled into a list of candidate system elements. These factors were then evaluated using expert knowledge derived from researchers with experience in transdisciplinary system design, peer-reviewed publications, and interpretive structural modeling methodologies. Pairwise relationships between the identified factors were assessed to construct the Structural Self-Interaction Matrix, following the standard ISM procedure. The relationships captured in the Structural Self-Interaction Matrix were then converted into reachability matrices, transitivity was incorporated, and hierarchical levels were determined to generate the final ISM digraph. This process enabled the systematic representation of interdependencies among design parameters and facilitated the evaluation of alternative actuation approaches for the left ventricular simulator. The main factors affecting design were categorized into two different groups with respect to their specifications for each LV simulator design approach: (a) common factors that exist in all design approaches, and (b) independent factors. Common factors are validly existing factors in all design approaches since they are related to the operating nature of human LV such as contraction rate and force of muscle fibers, controllability and preload ability of LV chamber, and common muscle fiber installation issues, like ease and adjustability of muscle fiber placement in the tissue material and structural integrity of muscle fibers with the tissue material of the LV chamber. Ease and adjustability of installation were included due to the shared influence for versatility and applicability of the actuation device. On the other hand, independent factors include the factors that vary and are distinctive for each LV simulator design approach. Design factors used to develop the beating LV simulator In this section, common and independent design factors used to develop the beating LV Simulator are reviewed. Common factors include the contraction rate of myocardial fibers, the contraction force of myocardial fibers, the controllability of LV motion, the preload ability of LV, and the ease and adjustability of installation and structural integrity of the actuators with other components. Independent design factors include pneumatic artificial muscle actuation, flexible bands actuation, and artificial muscle actuation of the beating LV simulator. Common design factors in the LV simulator. The contraction rate of the cardiomyocyte fibers influences various parameters on the contraction or pumping performance of the LV chamber, such as LV twist and untwisting rate, heartbeat per minute, etc. [ 30 ]. The connection between afterload and muscle fiber shortening rate is an inverse relationship. Additionally, the effect of the inotropic state of the cardiac fiber on the force-velocity relationship was mentioned as a shift up and right in the force-velocity curve, such that there is an increase in both maximum velocity and isometric force with increasing inotropy. That means boosting force generation capability by the actin and myosin filaments and improving the rate of generation with an increasing rate of cross-bridge turnover [ 31 ]. Also, a relation was stated between the LV untwisting rate and the peak twisting angle as well as LV end-systolic volume and ejection fraction [ 32 ]. Geyer et al. [ 33 ] describe the shear strain as the amount of distortion associated with the sliding of plane layers over each other. Evaluation of deformation on LV can be described in two ways: (1) a motion around a given point in tissue in terms of space and time and (2) the interaction between the strain rate and contraction performance. The myocardial deformation is described as follows: The ventricular muscle fibers contract in the longitudinal and circumferential dimensions, increase the wall thickness in the radial dimension, and twist along the long axis of the LV during cardiac systole [ 34 ]. The torsional behavior of LV is related to muscle contraction. whereas torsional rotation was highly related to transmural gradients of contractility [ 35 ]. The magnitude and timing of the LV torsion change the performance of the LV. The timing and function of the LV torsion can be defined as a measurement derived from the twisting or wringing motion around the long axis of LV [ 36 ]. The torsional movement stores energy for releasing at diastole to help ventricular filling which requires good timing of the cardiac muscle contractions. Another aspect of the controllability of LV motion or muscle contractions is the ability to mimic cardiomuscular dysfunctions [ 37 ]. Also, the time difference between peak rotations of the inner and outer layers of the LV wall was found to be significant and the pressure rate measurements matched with LV wall torsion [ 38 ]. The preload ability of the LV chamber can be explained by the Frank-Starling Law which expresses that the heart can increase its contraction capability by boosting venous return in stroke volume. The cardiac myocytes and other cardiac tissues stretch with the pressure generated by the atrium right before the contraction of the heart. Thus, it can be measured by the length of muscle fibers at the end of the diastole phase. The material property of the cardiac tissues has an important role in the preload ability of the chamber. The relationship between LV material properties and its performance was investigated and found to be highly related [ 39 , 40 ]. The main factors that affect LV preload can be listed as [ 31 ]: (1) LV compliance impacts the preload ability of the LV directly because higher compliance causes higher ventricular filling and more stretched myocytes; (2) Heart rate affects the LV preload by changing the filling time. Therefore, a higher heart rate adversely affects ventricular preload; (3) Most of the LV filling occurs with minimal contribution of atria at resting heart rates. Therefore, the assistance of atrial contraction can be neglected if the heart rate is in the normal resting heart rate range. Atrial contraction plays an important role when the heart rate escalates to the exercise range. The duration of the LV filling reduces significantly for high heart rates; (4) A weakening in the contraction of LV may create an increase in the preload ability due to the inability of blood ejection in normal volumes, which causes blood accumulation in LV and an increase in the preload ability of LV. The installation of muscle fibers or actuators must be easy to adjust because the orientation and location of the muscle fibers on the LV wall play an important role in the contraction or pumping performance of the LV. Additionally, the actuators/muscle fibers should be able to contract with the connecting tissue in both the systole and diastole. The helical ventricular myocardial band concept was developed to define principal, cumulative vectors, by taking into account the tissue architecture/structure and net forces developed within the ventricular mass [ 41 , 42 ]. Independent design factors in the LV simulator. Pneumatic Artificial Muscles are pressurized flexible air chambers that can contract by expanding in diameter with a pressurized air supply. The main advantages of Pneumatic Artificial Muscle are great force/weight ratio, low cost, flexible structure, and lightweight. Circumferential and longitudinal contraction and torsional deformations of the LV wall were investigated using a prototype made of plastic [ 43 ]. The performance of the prototyped LV chamber was found that the wall motion resembles a real LV and gave comparable results to human hemodynamic parameters. Pneumatic Artificial Muscles were also used on a mock LV chamber pump [ 44 ]. The developed Pneumatic Artificial Muscles were embedded in a silicon matrix tissue and attempted to mimic the motion of the LV by varying the applied pressure and configuration of Pneumatic Artificial Muscles. Strings or flexible bands can also be used as muscle-like mechanisms for beating LV simulators by pulling them with the help of linear or servo motors. Hanson et al. and Alazmani [ 45 , 46 ] developed hybrid heart simulator systems to simulate the mechanical properties of the beating LV. They suggested that the heart simulator should be able to simulate normal and pathological heart motion at rates of up to 150 bpm, pressure should be sensed and should be able to represent the motion of the heart slice by slice. The device was actuated by electromagnetic swing-arm actuators which are controll
## Related Clinical Research

- [Intensive blood pressure control linked to 15% lower 7-year dementia risk](https://medichelpline.com/clinical-feed/medical-news-today-0-intensive-blood-pressure-control-cuts-7-year-dementia-risk-by-15-study-finds.md)
- [My Health is Our Health: AHA and Ascension Seton launch Austin campaign on pregnancy and heart hea](https://medichelpline.com/clinical-feed/aha-news-0-american-heart-association-and-ascension-seton-launch-initiative-to-help-austin.md)
- [Stroke and Ischemic Heart Disease Trends in Western Sub‑Saharan Africa vs Global Progress, 1990–20](https://medichelpline.com/clinical-feed/medrxiv-0-divergent-trends-in-stroke-and-ischemic-heart-disease-mortality-and-disability.md)
- [Stopping Statins at Age 75 in Low‑Risk Adults: French Trial Found No Increase in Deaths](https://medichelpline.com/clinical-feed/stat-news-0-stopping-statins-in-people-over-75-at-low-risk-for-heart-disease-didn-t.md)
- [Multimodal extraction of heart disease risk factors from free-text and structured records using Li](https://medichelpline.com/clinical-feed/plos-one-0-leveraging-free-text-clinical-records-for-heart-disease-classification-through.md)

## Navigation
- [← Back to Cardiology Feed](https://medichelpline.com/clinical-feed/cardiology.md)
- [← All Clinical Specialties](https://medichelpline.com/clinical-feed.md)
## Medical & Regulatory Disclaimer

> [!CAUTION]
> MedicHelpline content is structured for research, educational, and professional discovery purposes. It does not constitute individual medical advice, clinical diagnosis, or treatment recommendations.
> Always verify dosing, contraindications, and regulatory alerts against official product labeling and primary regulatory sources before clinical decision-making.