Parallel Computing Performance of a 3D Cardiac Tissue Model

Objectives: Cryoablation is an effective alternative treatment for cardiac arrhythmias offering shortened recovery and reduced side effects. As the use of cryoablation increases, the need for new devices and procedures has emerged. This has been driven by technological limitations including lengthy periods to generate a single lesion (3–5 min), uncertain transmurality, and differential efficacy. Furthermore, due to limited ablation capacity under high heat loads, cryo has had limited success in the treatment of ventricular arrhythmias. To this end, in this study we evaluated a new cryoablation catheter, ICEolate, for the targeted ablation of cardiac tissue. Methods: Performance assessment included calorimetry, freeze zone isothermal distribution characterization and catheter ablation capacity in a submerged, circulating, heat-loaded ex vivo tissue model. A pilot in vivo study was also conducted to assess ablative capacity of the cryocatheter in a fully beating heart. Results: Ex vivo studies demonstrated ice formation at the tip of a cryocatheter within 5 s and a tip temperature of ~−150°C within 10 s. The device repeatedly generated freeze zones of 2 cm × 3 cm in less than 2 min. Tissue model studies revealed the generation of a full thickness (5–10 mm) cryogenic lesion within 1 min with an opposite (transmural) surface temperature of <−60°C under a circulating 37°C heat load. Pilot in vivo studies demonstrated the delivery of an ablative “dose,” producing a continuous full thickness transmural linear lesion in <60 s at both atrial and ventricular sites. Conclusion: These studies suggest that the supercritical nitrogen cryodevice and ICEolate cryocatheter may provide for rapid, effective, controllable freezing of targeted tissue. The ablative power, speed, and directional freeze characteristics also offer the potential of improved safety via a reduction in procedural time compared to current cryoablation devices. These technological developments may open new avenues for the application of cryo to treat other cardiac arrhythmogenic disorders.

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Modeling and characterizing parallel computing performance on heterogeneous networks of workstations

Proceedings Seventh IEEE Symposium on Parallel and Distributed Processing SPDP-95 ◽

10.1109/spdp.1995.530661 ◽

2002 ◽

Cited By ~ 37

Author(s):

Xiaodong Zhang ◽

Yong Yan

Keyword(s):

Parallel Computing ◽

Heterogeneous Networks ◽

Computing Performance

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Research on Parallel Computing Performance Based on Clusters

Lecture Notes in Electrical Engineering - Advances in Electrical Engineering and Electrical Machines ◽

10.1007/978-3-642-25905-0_72 ◽

2011 ◽

pp. 557-563

Author(s):

Li Geng ◽

Wang HaiTao

Keyword(s):

Parallel Computing ◽

Computing Performance

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Abstract 396: 3d-Engineered Aligned Co-axial Nanofibrous Cardiac Patch for Drug Screening and Cardiac Repair Applications

Circulation Research ◽

10.1161/res.127.suppl_1.396 ◽

2020 ◽

Vol 127 (Suppl_1) ◽

Author(s):

Mahmood Khan ◽

Divya Sridharan ◽

Naresh Kumar ◽

Arunumar Palaniappan ◽

Julie A Dougherty ◽

...

Keyword(s):

Drug Screening ◽

Connexin 43 ◽

Cardiac Tissue ◽

Cardiac Repair ◽

Confocal Imaging ◽

Test Machine ◽

Similar Response ◽

Calcium Cycling ◽

Tissue Model ◽

Cardiac Patch

Introduction: Recent studies have demonstrated the great potential of human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) for testing the efficacy of various cardiac drugs. Additionally, studies have shown that the hiPSC-CMs grown in a 3D environment express better physiological characteristics than 2D cultures. The convergence of polymeric cardiac patch technology with hiPSC-CMs has opened up innovative ways for generating biomimetic 3D cardiac tissues. Hypothesis: The central hypothesis of this study was to develop a 3D cardiac tissue model for pharmacological testing of various cardiac drugs on a 3D nanofibrous aligned co-axial cardiac patch. Methods: A co-axial (Co-A) PCL-gelatin aligned nanofibrous patch was fabricated using the electrospinning technique and its mechanical properties were assessed using Universal Test Machine. Then, the hiPSC-CMs were cultured on this Co-A patch for 2 weeks and the LDH assay was performed to determine the cell viability. The functionality of the cardiac patch was determined by an assessment of calcium cycling in hiPSC-CMs. Further, particle image velocimetry (PIV) and microelectrode array (MEA) was used to evaluate the physiological functionality of the cardiac patch in response to various cardiac drugs. Results: Our studies showed that the mean diameter and thickness of aligned Co-A nanofibrous patch was 578±184 nm and 115±11 μm respectively, while its tensile strength was 0.780 ± 0.098 MPa. Further, confocal imaging confirmed the core-shell structure of the Co-A patches with a core diameter of 2.21 ± 0.50 μm. Additionally, The hiPSC-CMs cultured on these aligned Co-A patches showed an aligned morphology and expressed Troponin-T, GATA4, α-sarcomeric actinin, and connexin-43. The hiPSC-CMs seeded on a 3D scaffold showed efficient calcium cycling properties, which were similar to the hiPSC-CMs cultured in 2D scaffold. Furthermore, PIV and MEA analysis showed that hiPSC-CMs cultured in 2D and 3D showed a similar response to various cardiac drugs, isoproterenol, verapamil and E4031. Conclusions: Overall, this study demonstrated a successful fabrication of aligned Co-A nanofibrous cardiac patch and its evaluation as a 3D cardiac tissue model in-vitro, which could be applied towards drug screening, toxicity studies and cardiac repair applications for ischemic heart disease.

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