In the realm of cardiac surgery, one of the most formidable challenges remains the effective treatment of ventricular tachycardia (VT), a life-threatening arrhythmia characterized by rapid heartbeats originating from the ventricles. Despite advancements in electrophysiological mapping and ablation techniques, epicardial ablation of VT continues to pose significant intraoperative challenges. The key obstacle lies in accurately identifying and targeting the arrhythmogenic substrate during surgery, often necessitating complex and time-consuming mapping procedures that demand a full electrophysiology team’s involvement. Enter an innovative solution poised to revolutionize the approach: the development of a patient-specific, flexible epicardial guide created through high-consistency rubber (HCR) silicone molding.
This landmark study, published in BioMedical Engineering OnLine, showcases a novel fabrication technique designed to tailor epicardial guides that conform precisely to individual patient anatomy. By integrating multimodal imaging data—including late gadolinium enhancement cardiac magnetic resonance (LGE–CMR) and cardiac computed tomography (CT) scans—the researchers successfully crafted high-fidelity inverted molds of affected myocardial regions. These molds then serve as the foundation for constructing custom guides, which act as intraoperative “blueprints,” delineating the spatial distribution of arrhythmogenic scar tissue. This breakthrough promises to streamline VT ablation, reducing reliance on live intraoperative mapping and enabling more targeted intervention.
The creation of the guide starts with advanced digital modeling. Using Meshmixer software, the team merged detailed LGE–CMR imaging data that highlight scar regions with structural cardiac CT images to generate a highly accurate three-dimensional negative mold of the patient’s epicardial surface. This mold, critical to replicating the unique cardiac topography, was prototyped via fused deposition modeling (FDM) 3D printing—a cost-effective method that lays down material layer-by-layer with precision. Subsequently, a viscous, high-consistency rubber silicone was meticulously milled, sculpted, and trimmed to fit the negative mold perfectly.
This HCR silicone material, specifically NuSil™ MED-4072 and MED-4080, was carefully selected for its remarkable balance of flexibility and durability. The silicone’s thickness was varied between 2.0 and 3.4 millimeters to determine the ideal structural configuration. After curing, the guides were subjected to rigorous autoclaving processes to test their resilience and sterility compatibility. The ultimate objective was to ensure that the guides retain their shape and functionality even under the harsh conditions of surgical sterilization and manipulation.
The study’s rigorous bench testing involved applying the fabricated guides onto ex vivo porcine hearts, a gold standard model for simulating human cardiac procedures due to anatomical similarities. Radiofrequency and cryo-ablation technologies were employed to mimic the actual VT treatment environment. Impressively, the guides maintained their structural integrity and neither deformed nor suffered material breakdown during repeated exposure to both thermal ablation modalities. This robust performance underscores the viability of HCR silicone as a surgical tool capable of enduring real-world operative stresses.
One of the most critical insights gained from the research was the identification of optimal thickness and hardness parameters that ensure both secure and gentle adherence to the epicardial surface. The study found that models measuring between 2.1 and 3.0 millimeters in thickness with a Shore A hardness of 70 afforded the best compromise. This combination provided enough rigidity to remain stable on a dynamically beating heart while preserving sufficient flexibility to avoid tissue trauma. Contrarily, the thinnest variant at 2.0 millimeters demonstrated excessive pliability, resulting in poor fixation and compromising precision during ablation.
Beyond mechanical performance, the guides’ potential to transform cardiac surgery workflows is profound. Traditionally, VT ablation demands the presence of an electrophysiology team throughout the procedure due to the intricate mapping requirements. The implementation of patient-specific epicardial guides could reduce this dependency, accelerating surgery times and lowering operational costs. Surgeons equipped with these blueprints can directly target the arrhythmogenic substrates with greater confidence and efficiency, potentially improving patient outcomes and reducing complication risks.
Furthermore, the cost-effectiveness of using HCR silicone molding compared to sophisticated 3D printing materials like photopolymers or metal resins is a substantial advantage. High-consistency silicone is readily available, relatively inexpensive, and amenable to rapid prototyping, thus enhancing accessibility for healthcare centers worldwide, including resource-limited settings. This democratization of customized surgical tools represents a significant advance towards personalized cardiac care.
The implications of this research extend beyond ventricular tachycardia ablation. The methodology of using patient-specific molds combined with flexible silicone guides could find applications in other cardiac interventions requiring precise anatomical localization, such as epicardial pacing lead placement or surgical repair of myocardial scars. It also paves the way for further integration of bioengineering and clinical cardiology, fostering innovations that blend imaging, materials science, and surgical precision.
Moving forward, clinical trials will be critical to validating the efficacy and safety of these silicone epicardial guides in live human surgeries. Questions remain about the guides’ behavior in a beating human heart’s complex physiological environment, their interaction with surrounding tissues, and long-term biocompatibility. Moreover, refining the manufacturing workflow to reduce production time and streamline customization based on real-time imaging data will be essential for widespread adoption.
In conclusion, the creation of flexible, cost-effective, patient-specific epicardial guides through high-consistency rubber silicone molding marks a significant technological leap in the surgical management of ventricular tachycardia. By offering a tangible, durable, and anatomically accurate tool to surgeons, this innovation holds immense promise for enhancing procedural success rates and transforming cardiac arrhythmia treatment. The future of tailored cardiac surgery is here, driven by cutting-edge materials science and precision imaging techniques.
Subject of Research:
Article Title: Development of a patient-specific epicardial guide for ventricular tachycardia ablation surgery using high-consistency rubber silicone molding
Article References:
Kronenberger, R., Candelari, M., Cappello, I.A. et al. Development of a patient-specific epicardial guide for ventricular tachycardia ablation surgery using high-consistency rubber silicone molding. BioMed Eng OnLine 24, 133 (2025). https://doi.org/10.1186/s12938-025-01435-z
Image Credits: AI Generated
DOI: 10 November 2025
