Home Simulation of intracardiac electrograms around acute ablation lesions
Article Open Access

Simulation of intracardiac electrograms around acute ablation lesions

  • Joachim Greiner EMAIL logo , Stefan Pollnow , Steffen Schuler , Gustavo Lenis , Gunnar Seemann and Olaf Dössel
Published/Copyright: September 30, 2016
Download Article (PDF)
Become an author with De Gruyter Brill
Author Information Explore this Subject
Current Directions in Biomedical Engineering
From the journal Current Directions in Biomedical Engineering Volume 2 Issue 1

Abstract

Radiofrequency ablation (RFA) is a widely used clinical treatment for many types of cardiac arrhythmias. However, nontransmural lesions and gaps between linear lesions often lead to recurrence of the arrhythmia. Intracardiac electrograms (IEGMs) provide real-time information regarding the state of the cardiac tissue surrounding the catheter tip. Nevertheless, the formation and interpretation of IEGMs during the RFA procedure is complex and yet not fully understood. In this in-silico study, we propose a computational model for acute ablation lesions. Our model consists of a necrotic scar core and a border zone, describing irreversible and reversible temperature induced electrophysiological phenomena. These phenomena are modeled by varying the intra- and extracellular conductivity of the tissue as well as a regulating zone factor. The computational model is evaluated regarding its feasibility and validity. Therefore, this model was compared to an existing one and to clinical measurements of five patients undergoing RFA. The results show that the model can indeed be used to recreate IEGMs. We computed IEGMs arising from complex ablation scars, such as scars with gaps or two overlapping ellipsoid scars. For orthogonal catheter orientation, the presence of a second necrotic core in the near-field of a punctiform acute ablation lesion had minor impact on the resulting signal morphology. The presented model can serve as a base for further research on the formation and interpretation of IEGMs.

Keywords: acute ablation lesions; in-silico modelling; intracardiac electrograms; radiofrequency ablation

1 Introduction

Radiofrequency ablation (RFA) is the gold standard procedure for many forms of cardiac arrhythmias, including atrial fibrillation, when drug therapy is not effective. A corner stone for RFA success is the creation of transmural and continuous scars arising from elevated temperatures due to radiofrequency currents. Unfortunately, the recurrence rate of arrhythmias is relatively high at 35–45% [1], which means that patients often have to undergo a second procedure. However, to date, there are no reliable criteria for evaluating acute ablation lesions and monitoring the ablation process. Animal and clinical studies have shown that electrogram (EGM)-based criteria can be used to evaluate the formation of single point lesions [2], [3]. In this in-silico study, we investigated the influence of ablation lesions and catheter orientation on the morphology of intracardiac electrograms (IEGMs). We extended an existing model of an acute ablation lesion to cover more complex geometries; that is, those consisting of two point-shaped lesions. By evaluating the simulated IEGMs, new parameters can be identified to assess complex ablation lesions.

2 Methods

2.1 Simulation setup

For our in-silico studies, we solved the finite element bidomain formulation using the cardiac simulation framework acCELLerate [4]. We adapted our computational model of an acute ablation lesion from the model of Keller et al. [5]. The simulations were performed on an isotropic patch of myocardium with a size of 40 mm × 24 mm × 22 mm and a spatial resolution of 0.2 mm. An 8F (2.7 mm) non-irrigated ablation catheter with an 8 mm distal electrode and a 1.2 mm proximal electrode was placed either orthogonally or parallel to the myocardium. The catheter tip deforms the tissue surface by 1 mm for the orthogonal orientation, whereas the parallel orientation results in no tissue deformation. An intracellular stimulus current was applied at the left tissue boundary to initiate excitation propagation. The extracellular and intracellular conductivities of the myocardium were set to 0.264 S/m [6] and 0.40 S/m, respectively, which yielded a conduction velocity (CV) of 800 mm/s (see Table 1). According to Clayton et al. [7], both of these values are within the range of experimental measurements. The myocardium is completely surrounded by blood with an extracellular conductivity of 0.7 S/m and no intracellular conductivity [8]. The conductivity of the electrode was defined to be 10,000 times higher than the conductivity of blood, which resulted in a near-equipotential volume inside the metal. An isolating material was placed between the distal and proximal electrode. The boundaries of the intra- and extracellular domains were implemented with no-flux Neumann conditions and the following constraint was used to fix the extracellular potential ϕe:

Table 1

Overview of intra- and extracellular conductivities and CV for several temperature ranges.

Materialσi (S/m)σe (S/m)CV (mm/s)
Myocardium0.400.264800
Blood10−100.70–
Lesion (40–43°C)0.47–0.530.264844–873
Lesion (43–46°C)0.53–0.360.264873–784
Lesion (46–50°C)0.36–0.010.264784–160
Lesion (necrotic)10−100.10–
Electrode10−107 ⋅ 103–
Isolation10−1010−10–

The intracellular conductivity in the border zones is continuous and is given as the range of values in this zone. We assumed a membrane capacity Cm of 0.1 μF/cm2 and surface to volume ratio β of 100 mm−1.

(1)∫Ωϕe d⁢Ω=0.
Figure 1 Exemplary simulation setup for orthogonal catheter orientation. The whole setup is surrounded by blood (not shown in this figure). Legend: Acute border zone (50°C 40°C), necrotic scar core (), myocardium (), electrode (), isolation ().
Figure 1

Exemplary simulation setup for orthogonal catheter orientation. The whole setup is surrounded by blood (not shown in this figure). Legend: Acute border zone (50°C 40°C), necrotic scar core (), myocardium (), electrode (), isolation ().

2.2 Ablation models

Keller et al. [5] modeled an acute ablation lesion with a necrotic core and a border zone consisting of six different layers with properties of heated myocardium. We expanded this model to a continuous temperature distribution, where we calculated electrophysiological parameters uniquely for each voxel in the border zone. The action potential (AP) changes were modeled in a ten Tusscher cell model, which was adapted for ischemia phase 1a by Wilhelms et al. [5], [9]. The lesion model assumes a maximum scar width of 10 mm for orthogonal orientation (for parallel orientation: 12.8 mm) and a scar width to depth ratio of 1.25 for orthogonal catheter orientation (for parallel orientation: 1.6) [5]. The intracellular conductivity of the necrotic scar core was set to zero and the extracellular conductivity was set to 0.1 S/m. We estimated the intracellular conductivity for each temperature using the findings of the hyperthermia experiments from Simmers et al. [10]. Subsequently, small patches of myocardium (120 × 30 × 65 voxel elements with a spatial resolution of 0.2 mm) were used to determine intracellular conductivities for different temperatures, while the corresponding extracellular conductivity remained constant. We calculated the CV by using the steepest point in the AP upstroke as reference point for cellular activation. CV over intracellular conductivity σi was then interpolated with cubic splines to obtain a function for CV (see Table 1). The second part of this study deals with a simplified in-silico model for complex ablation lesions. As a first approach, we assumed that the border zones of the first ablation lesion were completely cooled down by blood flow and heat loss due to local tissue perfusion. Inflammation as well as edemas were excluded in this model. The second ablation lesion was set along the x-axis of the first ablation scar. The distance between the center of both lesions was varied between 6.6 and 12.6 mm with a step-width of 2 mm, representing all important scar configurations from mostly overlapping scar cores to ablation lesions with gaps. If the passive necrotic core overlapped the border zones of the second lesion, necrotic tissue was assigned to this region.

2.3 Simulation and analysis of IEGMs

We referenced the simulated extracellular potentials with the tissue-distant top voxel layer of our computational setup. The bipolar EGM was obtained by subtracting the proximal EGM from the distal EGM. In order to compare clinical measurements with simulated IEGMs, a transfer function with a first order butterworth highpass at 30 Hz and a first order butterworth lowpass at 250 Hz was used [5]. For comparison, we automatically annotated the following markers in the simulated data as well as from five patients undergoing RFA procedure in the right atrium: positive peak amplitude, negative peak amplitude and the maximum absolute first derivative between positive and negative peak. The deviation of computed IEGMs and clinical IEGMs was quantified by the deviation factor QV:

(2)QV=∑∀i1(σc⁢l⁢i⁢n⁢i⁢c⁢a⁢l,i)2⋅(Ec⁢l⁢i⁢n⁢i⁢c⁢a⁢l,i−Ec⁢o⁢m⁢p,i)2,

where σclinical is the standard deviation and E is the mean value of each charactistic.

3 Results

Extracted quantified signal statistics are shown in Table 2. For orthogonal catheter orientation, extracted mean values are in high accordance with the distribution extracted from clinical IEGMs, resulting in relatively a small QV value of 2. For parallel catheter orientation with distal to proximal wave propagation, all mean values are in line with the clinical IEGMs, except the upstroke reduction in the distal IEGM. Therefore, QV results in a rather high value of 107. Proximal to distal wave propagation lead to a similar pattern, but with less total deviation, resulting in a QV value of 59.

Table 2

Relative changes during ablation in measured and simulated IEGMs characteristics (mean value and standard deviation).

Clinical IEGMsSimulated IEGMs
OrientationRel. maximumRel. minimumRel. derivativeRel. maximumRel. minimumRel. derivative
Orthogonal, distal−0.17 ± 0.27−0.94 ± 0.10−0.80 ± 0.09−0.13 ± 0.00−0.81 ± 0.00−0.78 ± 0.00
Orthogonal, proximal–––−0.04 ± 0.00−0.64 ± 0.00−0.49 ± 0.00
Orthogonal, bipolar−0.95 ± 0.17−0.20 ± 0.33−0.79 ± 0.10−0.87 ± 0.00−0.33 ± 0.00−0.81 ± 0.00
Parallel – DP, distal−0.27 ± 0.53−1.04 ± 0.14−0.81 ± 0.05−0.18 ± 0.00−0.73 ± 0.00−0.31 ± 0.00
Parallel – DP, proximal−0.15 ± 0.23−0.09 ± 0.530.09 ± 0.41−0.52 ± 0.00−0.23 ± 0.000.06 ± 0.00
Parallel – DP, bipolar−1.06 ± 0.37−0.14 ± 0.54−0.24 ± 0.82−0.73 ± 0.00−0.27 ± 0.00−0.04 ± 0.00
Parallel – PD, distal−0.31 ± 0.21−1.00 ± 0.12−0.88 ± 0.10−0.31 ± 0.00−0.73 ± 0.00−0.53 ± 0.00
Parallel – PD, proximal−0.22 ± 0.21−0.46 ± 0.12−0.45 ± 0.190.09 ± 0.00−0.20 ± 0.000.17 ± 0.00
Parallel – PD, bipolar−0.59 ± 0.17−0.39 ± 0.03−0.46 ± 0.13−0.80 ± 0.00−0.25 ± 0.00−0.25 ± 0.00

For parallel catheter orientation, we distinguished between distal to proximal (DP) and proximal to distal (PD) wave propagation.

In Figure 2, some of the simulated IEGMs are presented in their filtered state together with the clinical signals for orthogonal catheter orientation. For all cases only a slight change was determined in the proximal IEGM. Therefore, the changes in bipolar IEGMs were dominated by the distal IEGM. This relation was also present for parallel catheter orientation. For complex scars, the visualization goal is not to observe individual changes, but rather to grasp the overall minor changes in signal morphology. Neither the morphology of the IEGM, nor the extracted signal statistic showed major changes.

Figure 2 Comparison of filtered simulated IEGMs for point-shaped and complex ablation lesions, as well as clinical filtered IEGMs, before and after RFA, for orthogonal catheter orientation. Scar Legend: Point-shaped scars (), distance of complex scars (12.6 mm 6.6 mm, 12.6 mm 6.6 mm). Time Legend: Before ablation (), after ablation ().
Figure 2

Comparison of filtered simulated IEGMs for point-shaped and complex ablation lesions, as well as clinical filtered IEGMs, before and after RFA, for orthogonal catheter orientation. Scar Legend: Point-shaped scars (), distance of complex scars (12.6 mm 6.6 mm, 12.6 mm 6.6 mm). Time Legend: Before ablation (), after ablation ().

4 Discussion

In this computational study, we investigated the morphological changes of IEGMs shortly after the RFA procedure. For this purpose, an existing model of an acute ablation lesion was developed further and subsequently, a first model of a complex ablation lesion was introduced. The in-silico experiments were performed with an 8F non-irrigated ablation catheter, which is often used in clinical ablation procedures. Additionally, the orientation of the ablation catheter and the distances between two ablation lesions were varied on the three-dimensional myocardial patch. This computational setup offered the possibility to evaluate the distal, proximal and bipolar IEGMs for varying lesion geometry and transmurality.

We compared the expanded model with the computational model from Keller et al. [5] and clinical signals during RFA procedures. Compared to the original model from [5], the deviation factor QV decreased from 513 to 167. Hereby, a better statistical agreement between our simulated IEGMs and the clinical IEGMs was found with the new ablation lesion model. The simulation setup of the complex ablation lesions was a first step to reproduce more realistic clinical ablation patterns consisting of several point-shaped lesions. With our simplified necrotic core-model it is not feasible to detect gaps between two ablation scars nor to identify correspondent markers in the IEGMs, especially in retrospect with the natural deviation range seen in the clinical data set. To the best of our knowledge, no computational model exist to investigate more complex acute ablation lesions and cardiac electrophysiology around these areas simultaneously. In a next step, we will implement further modular expansions to the ablation process. We can computationally substantiate many presumptions, such as heat distribution and bio-heat transfer, blood flow and applied contact-force. Moreover, non-irrigated or irrigated ablation catheters of different geometries could be investigated. Simulated IEGMs of this new model have to be compared with clinical signals of more complex ablation lesions, such as linear lesions. Hereby, we will evaluate the changes of the IEGMs to identify robust criteria for describing lesion geometry as well as transmurality.

Finally, we want to highlight that clinical filter parameters are usually overlooked when talking about IEGMs. Signal morphology is strongly dependent on the order as well as on the chosen cut-off frequencies of the filter and therefore, these parameters have to be carefully considered when comparing IEGMs.

Acknowledgement

The authors would like to thank Matthias Werber for his support in the in-silico experiments.

Author’s Statement

Research funding: Stefan Pollnow is supported by a scholarship of the Karlsruhe School of Optics and Photonics (KSOP). Conflict of interest: The authors declare that they have no competing interests. Informed consent: Informed consent is not applicable. Ethical approval: The conducted research is not related to either human or animal use.

References

[1] Shurrab M, Biase LD, Briceno DF, Kaoutskaia A, Haj-Yahia S, Newman D, et al. Impact of contact force technology on atrial fibrillation ablation: a meta-analysis. J Am Heart Assoc. 2015;4:e002476.10.1161/JAHA.115.002476Search in Google Scholar PubMed PubMed Central

[2] Otomo K, Uno K, Fujiwara H, Isobe M, Iesaka Y. Local unipolar and bipolar electrogram criteria for evaluating the transmurality of atrial ablation lesions at different catheter orientations relative to the endocardial surface. Heart Rhythm. 2010;7:1291–300.10.1016/j.hrthm.2010.06.014Search in Google Scholar PubMed

[3] Bortone A, Appetiti A, Bouzeman A, Maupas E, Ciobotaru V, Boulenc JM, et al. Unipolar signal modification as a guide for lesion creation during radiofrequency application in the left atrium: a prospective study in humans in the setting of paroxysmal atrial fibrillation catheter ablation. Circ Arrhythmia Electrophysiol. 2013;6:1095–102.10.1161/CIRCEP.113.000749Search in Google Scholar PubMed

[4] Seemann G, Sachse FB, Karl M, Weiss DL, Heuveline V, Dössel O. Framework for modular, flexible and efficient solving the cardiac bidomain equation using PETSc. Progr Ind Math. 2010;15:363–9.10.1007/978-3-642-12110-4_55Search in Google Scholar

[5] Keller MW, Schuler S, Wilhelms M, Lenis G, Seemann G, Schmitt C, et al. Characterization of radiofrequency ablation lesion development based on simulated and measured intracardiac electrograms. IEEE Trans Biomed Eng. 2014;61:2467–78.10.1109/TBME.2014.2322515Search in Google Scholar PubMed

[6] Schwab BC, Seemann G, Lasher RA, Torres NS, Wulfers EM, Arp M, et al. Quantitative analysis of cardiac tissue including fibroblasts using three-dimensional confocal microscopy and image reconstruction: towards a basis for electrophysiological modeling. IEEE Trans Med Imaging. 2013;32:862–72.10.1109/TMI.2013.2240693Search in Google Scholar PubMed PubMed Central

[7] Clayton RH, Bernus O, Cherry EM, Dierckx H, Fenton FH, Mirabella L, et al. Models of cardiac tissue electrophysiology: progress, challenges and open questions. Prog Biophys Mol Biol. 2011;104:22–48.10.1016/j.pbiomolbio.2010.05.008Search in Google Scholar PubMed

[8] Gabriel S, Lau RW, Gabriel C. The dielectric properties of biological tissues: III. parametric models for the dielectric spectrum of tissues. Phys Med Bio. 1996;41:2271.10.1088/0031-9155/41/11/003Search in Google Scholar PubMed

[9] Wilhelms M, Dössel O, Seemann G. In silico investigation of electrically silent acute cardiac ischemia in the human ventricles. IEEE Trans Biomed Eng. 2011;58:2961–4.10.1109/TBME.2011.2159381Search in Google Scholar PubMed

[10] Simmers TA, De Bakker JM, Wittkampf FH, Hauer RN. Effects of heating on impulse propagation in superfused canine myocardium. J Amer Coll Cardiol. 1995;25:1457–64.10.1016/0735-1097(94)00559-9Search in Google Scholar PubMed

Published Online: 2016-9-30
Published in Print: 2016-9-1

©2016 Joachim Greiner et al., licensee De Gruyter.

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Articles in the same Issue

  1. Synthesis and characterization of PIL/pNIPAAm hybrid hydrogels
  2. Novel blood protein based scaffolds for cardiovascular tissue engineering
  3. Cell adhesion and viability of human endothelial cells on electrospun polymer scaffolds
  4. Effects of heat treatment and welding process on superelastic behaviour and microstructure of micro electron beam welded NiTi
  5. Long-term stable modifications of silicone elastomer for improved hemocompatibility
  6. The effect of thermal treatment on the mechanical properties of PLLA tubular specimens
  7. Biocompatible wear-resistant thick ceramic coating
  8. Protection of active implant electronics with organosilicon open air plasma coating for plastic overmolding
  9. Examination of dielectric strength of thin Parylene C films under various conditions
  10. Open air plasma deposited antimicrobial SiOx/TiOx composite films for biomedical applications
  11. Systemic analysis about residual chloroform in PLLA films
  12. A macrophage model of osseointegration
  13. Towards in silico prognosis using big data
  14. Technical concept and evaluation of a novel shoulder simulator with adaptive muscle force generation and free motion
  15. Usability evaluation of a locomotor therapy device considering different strategies
  16. Hypoxia-on-a-chip
  17. Integration of a semi-automatic in-vitro RFA procedure into an experimental setup
  18. Fabrication of MEMS-based 3D-μECoG-MEAs
  19. High speed digital interfacing for a neural data acquisition system
  20. Bionic forceps for the handling of sensitive tissue
  21. Experimental studies on 3D printing of barium titanate ceramics for medical applications
  22. Patient specific root-analogue dental implants – additive manufacturing and finite element analysis
  23. 3D printing – a key technology for tailored biomedical cell culture lab ware
  24. 3D printing of hydrogels in a temperature controlled environment with high spatial resolution
  25. Biocompatibility of photopolymers for additive manufacturing
  26. Biochemical piezoresistive sensors based on pH- and glucose-sensitive hydrogels for medical applications
  27. Novel wireless measurement system of pressure dedicated to in vivo studies
  28. Portable auricular device for real-time swallow and chew detection
  29. Detection of miRNA using a surface plasmon resonance biosensor and antibody amplification
  30. Simulation and evaluation of stimulation scenarios for targeted vestibular nerve excitation
  31. Deep brain stimulation: increasing efficiency by alternative waveforms
  32. Prediction of immediately occurring microsleep events from brain electric signals
  33. Determining cardiac vagal threshold from short term heart rate complexity
  34. Classification of cardiac excitation patterns during atrial fibrillation
  35. An algorithm to automatically determine the cycle length coverage to identify rotational activity during atrial fibrillation – a simulation study
  36. Deriving respiration from high resolution 12-channel-ECG during cycling exercise
  37. Reducing of gradient induced artifacts on the ECG signal during MRI examinations using Wilcoxon filter
  38. Automatic detection and mapping of double potentials in intracardiac electrograms
  39. Modeling the pelvic region for non-invasive pelvic intraoperative neuromonitoring
  40. Postprocessing algorithm for automated analysis of pelvic intraoperative neuromonitoring signals
  41. Best practice: surgeon driven application in pelvic operations
  42. Vasomotor assessment by camera-based photoplethysmography
  43. Classification of morphologic changes in photoplethysmographic waveforms
  44. Novel computation of pulse transit time from multi-channel PPG signals by wavelet transform
  45. Efficient design of FIR filter based low-pass differentiators for biomedical signal processing
  46. Nonlinear causal influences assessed by mutual compression entropy
  47. Comparative study of methods for solving the correspondence problem in EMD applications
  48. fNIRS for future use in auditory diagnostics
  49. Semi-automated detection of fractional shortening in zebrafish embryo heart videos
  50. Blood pressure measurement on the cheek
  51. Derivation of the respiratory rate from directly and indirectly measured respiratory signals using autocorrelation
  52. Left cardiac atrioventricular delay and inter-ventricular delay in cardiac resynchronization therapy responder and non-responder
  53. An automatic systolic peak detector of blood pressure waveforms using 4th order cumulants
  54. Real-time QRS detection using integrated variance for ECG gated cardiac MRI
  55. Preprocessing of unipolar signals acquired by a novel intracardiac mapping system
  56. In-vitro experiments to characterize ventricular electromechanics
  57. Continuous non-invasive monitoring of blood pressure in the operating room: a cuffless optical technology at the fingertip
  58. Application of microwave sensor technology in cardiovascular disease for plaque detection
  59. Artificial blood circulatory and special Ultrasound Doppler probes for detecting and sizing gaseous embolism
  60. Detection of microsleep events in a car driving simulation study using electrocardiographic features
  61. A method to determine the kink resistance of stents and stent delivery systems according to international standards
  62. Comparison of stented bifurcation and straight vessel 3D-simulation with a prior simulated velocity profile inlet
  63. Transient Euler-Lagrange/DEM simulation of stent thrombosis
  64. Automated control of the laser welding process of heart valve scaffolds
  65. Automation of a test bench for accessing the bendability of electrospun vascular grafts
  66. Influence of storage conditions on the release of growth factors in platelet-rich blood derivatives
  67. Cryopreservation of cells using defined serum-free cryoprotective agents
  68. New bioreactor vessel for tissue engineering of human nasal septal chondrocytes
  69. Determination of the membrane hydraulic permeability of MSCs
  70. Climate retainment in carbon dioxide incubators
  71. Multiple factors influencing OR ventilation system effectiveness
  72. Evaluation of an app-based stress protocol
  73. Medication process in Styrian hospitals
  74. Control tower to surgical theater
  75. Development of a skull phantom for the assessment of implant X-ray visibility
  76. Surgical navigation with QR codes
  77. Investigation of the pressure gradient of embolic protection devices
  78. Computer assistance in femoral derotation osteotomy: a bottom-up approach
  79. Automatic depth scanning system for 3D infrared thermography
  80. A service for monitoring the quality of intraoperative cone beam CT images
  81. Resectoscope with an easy to use twist mechanism for improved handling
  82. In vitro simulation of distribution processes following intramuscular injection
  83. Adjusting inkjet printhead parameters to deposit drugs into micro-sized reservoirs
  84. A flexible standalone system with integrated sensor feedback for multi-pad electrode FES of the hand
  85. Smart control for functional electrical stimulation with optimal pulse intensity
  86. Tactile display on the remaining hand for unilateral hand amputees
  87. Effects of sustained electrical stimulation on spasticity assessed by the pendulum test
  88. An improved tracking framework for ultrasound probe localization in image-guided radiosurgery
  89. Improvement of a subviral particle tracker by the use of a LAP-Kalman-algorithm
  90. Learning discriminative classification models for grading anal intraepithelial neoplasia
  91. Regularization of EIT reconstruction based on multi-scales wavelet transforms
  92. Assessing MRI susceptibility artefact through an indicator of image distortion
  93. EyeGuidance – a computer controlled system to guide eye movements
  94. A framework for feedback-based segmentation of 3D image stacks
  95. Doppler optical coherence tomography as a promising tool for detecting fluid in the human middle ear
  96. 3D Local in vivo Environment (LivE) imaging for single cell protein analysis of bone tissue
  97. Inside-Out access strategy using new trans-vascular catheter approach
  98. US/MRI fusion with new optical tracking and marker approach for interventional procedures inside the MRI suite
  99. Impact of different registration methods in MEG source analysis
  100. 3D segmentation of thyroid ultrasound images using active contours
  101. Designing a compact MRI motion phantom
  102. Cerebral cortex classification by conditional random fields applied to intraoperative thermal imaging
  103. Classification of indirect immunofluorescence images using thresholded local binary count features
  104. Analysis of muscle fatigue conditions using time-frequency images and GLCM features
  105. Numerical evaluation of image parameters of ETR-1
  106. Fabrication of a compliant phantom of the human aortic arch for use in Particle Image Velocimetry (PIV) experimentation
  107. Effect of the number of electrodes on the reconstructed lung shape in electrical impedance tomography
  108. Hardware dependencies of GPU-accelerated beamformer performances for microwave breast cancer detection
  109. Computer assisted assessment of progressing osteoradionecrosis of the jaw for clinical diagnosis and treatment
  110. Evaluation of reconstruction parameters of electrical impedance tomography on aorta detection during saline bolus injection
  111. Evaluation of open-source software for the lung segmentation
  112. Automatic determination of lung features of CF patients in CT scans
  113. Image analysis of self-organized multicellular patterns
  114. Effect of key parameters on synthesis of superparamagnetic nanoparticles (SPIONs)
  115. Radiopacity assessment of neurovascular implants
  116. Development of a desiccant based dielectric for monitoring humidity conditions in miniaturized hermetic implantable packages
  117. Development of an artifact-free aneurysm clip
  118. Enhancing the regeneration of bone defects by alkalizing the peri-implant zone – an in vitro approach
  119. Rapid prototyping of replica knee implants for in vitro testing
  120. Protecting ultra- and hyperhydrophilic implant surfaces in dry state from loss of wettability
  121. Advanced wettability analysis of implant surfaces
  122. Patient-specific hip prostheses designed by surgeons
  123. Plasma treatment on novel carbon fiber reinforced PEEK cages to enhance bioactivity
  124. Wear of a total intervertebral disc prosthesis
  125. Digital health and digital biomarkers – enabling value chains on health data
  126. Usability in the lifecycle of medical software development
  127. Influence of different test gases in a non-destructive 100% quality control system for medical devices
  128. Device development guided by user satisfaction survey on auricular vagus nerve stimulation
  129. Empirical assessment of the time course of innovation in biomedical engineering: first results of a comparative approach
  130. Effect of left atrial hypertrophy on P-wave morphology in a computational model
  131. Simulation of intracardiac electrograms around acute ablation lesions
  132. Parametrization of activation based cardiac electrophysiology models using bidomain model simulations
  133. Assessment of nasal resistance using computational fluid dynamics
  134. Resistance in a non-linear autoregressive model of pulmonary mechanics
  135. Inspiratory and expiratory elastance in a non-linear autoregressive model of pulmonary mechanics
  136. Determination of regional lung function in cystic fibrosis using electrical impedance tomography
  137. Development of parietal bone surrogates for parietal graft lift training
  138. Numerical simulation of mechanically stimulated bone remodelling
  139. Conversion of engineering stresses to Cauchy stresses in tensile and compression tests of thermoplastic polymers
  140. Numerical examinations of simplified spondylodesis models concerning energy absorption in magnetic resonance imaging
  141. Principle study on the signal connection at transabdominal fetal pulse oximetry
  142. Influence of Siluron® insertion on model drug distribution in the simulated vitreous body
  143. Evaluating different approaches to identify a three parameter gas exchange model
  144. Effects of fibrosis on the extracellular potential based on 3D reconstructions from histological sections of heart tissue
  145. From imaging to hemodynamics – how reconstruction kernels influence the blood flow predictions in intracranial aneurysms
  146. Flow optimised design of a novel point-of-care diagnostic device for the detection of disease specific biomarkers
  147. Improved FPGA controlled artificial vascular system for plethysmographic measurements
  148. Minimally spaced electrode positions for multi-functional chest sensors: ECG and respiratory signal estimation
  149. Automated detection of alveolar arches for nasoalveolar molding in cleft lip and palate treatment
  150. Control scheme selection in human-machine- interfaces by analysis of activity signals
  151. Event-based sampling for reducing communication load in realtime human motion analysis by wireless inertial sensor networks
  152. Automatic pairing of inertial sensors to lower limb segments – a plug-and-play approach
  153. Contactless respiratory monitoring system for magnetic resonance imaging applications using a laser range sensor
  154. Interactive monitoring system for visual respiratory biofeedback
  155. Development of a low-cost senor based aid for visually impaired people
  156. Patient assistive system for the shoulder joint
  157. A passive beating heart setup for interventional cardiology training
https://doi.org/10.1515/cdbme-2016-0134
Keywords for this article
acute ablation lesions; in-silico modelling; intracardiac electrograms; radiofrequency ablation
Creative Commons
BY-NC-ND 4.0

Articles in the same Issue

  1. Synthesis and characterization of PIL/pNIPAAm hybrid hydrogels
  2. Novel blood protein based scaffolds for cardiovascular tissue engineering
  3. Cell adhesion and viability of human endothelial cells on electrospun polymer scaffolds
  4. Effects of heat treatment and welding process on superelastic behaviour and microstructure of micro electron beam welded NiTi
  5. Long-term stable modifications of silicone elastomer for improved hemocompatibility
  6. The effect of thermal treatment on the mechanical properties of PLLA tubular specimens
  7. Biocompatible wear-resistant thick ceramic coating
  8. Protection of active implant electronics with organosilicon open air plasma coating for plastic overmolding
  9. Examination of dielectric strength of thin Parylene C films under various conditions
  10. Open air plasma deposited antimicrobial SiOx/TiOx composite films for biomedical applications
  11. Systemic analysis about residual chloroform in PLLA films
  12. A macrophage model of osseointegration
  13. Towards in silico prognosis using big data
  14. Technical concept and evaluation of a novel shoulder simulator with adaptive muscle force generation and free motion
  15. Usability evaluation of a locomotor therapy device considering different strategies
  16. Hypoxia-on-a-chip
  17. Integration of a semi-automatic in-vitro RFA procedure into an experimental setup
  18. Fabrication of MEMS-based 3D-μECoG-MEAs
  19. High speed digital interfacing for a neural data acquisition system
  20. Bionic forceps for the handling of sensitive tissue
  21. Experimental studies on 3D printing of barium titanate ceramics for medical applications
  22. Patient specific root-analogue dental implants – additive manufacturing and finite element analysis
  23. 3D printing – a key technology for tailored biomedical cell culture lab ware
  24. 3D printing of hydrogels in a temperature controlled environment with high spatial resolution
  25. Biocompatibility of photopolymers for additive manufacturing
  26. Biochemical piezoresistive sensors based on pH- and glucose-sensitive hydrogels for medical applications
  27. Novel wireless measurement system of pressure dedicated to in vivo studies
  28. Portable auricular device for real-time swallow and chew detection
  29. Detection of miRNA using a surface plasmon resonance biosensor and antibody amplification
  30. Simulation and evaluation of stimulation scenarios for targeted vestibular nerve excitation
  31. Deep brain stimulation: increasing efficiency by alternative waveforms
  32. Prediction of immediately occurring microsleep events from brain electric signals
  33. Determining cardiac vagal threshold from short term heart rate complexity
  34. Classification of cardiac excitation patterns during atrial fibrillation
  35. An algorithm to automatically determine the cycle length coverage to identify rotational activity during atrial fibrillation – a simulation study
  36. Deriving respiration from high resolution 12-channel-ECG during cycling exercise
  37. Reducing of gradient induced artifacts on the ECG signal during MRI examinations using Wilcoxon filter
  38. Automatic detection and mapping of double potentials in intracardiac electrograms
  39. Modeling the pelvic region for non-invasive pelvic intraoperative neuromonitoring
  40. Postprocessing algorithm for automated analysis of pelvic intraoperative neuromonitoring signals
  41. Best practice: surgeon driven application in pelvic operations
  42. Vasomotor assessment by camera-based photoplethysmography
  43. Classification of morphologic changes in photoplethysmographic waveforms
  44. Novel computation of pulse transit time from multi-channel PPG signals by wavelet transform
  45. Efficient design of FIR filter based low-pass differentiators for biomedical signal processing
  46. Nonlinear causal influences assessed by mutual compression entropy
  47. Comparative study of methods for solving the correspondence problem in EMD applications
  48. fNIRS for future use in auditory diagnostics
  49. Semi-automated detection of fractional shortening in zebrafish embryo heart videos
  50. Blood pressure measurement on the cheek
  51. Derivation of the respiratory rate from directly and indirectly measured respiratory signals using autocorrelation
  52. Left cardiac atrioventricular delay and inter-ventricular delay in cardiac resynchronization therapy responder and non-responder
  53. An automatic systolic peak detector of blood pressure waveforms using 4th order cumulants
  54. Real-time QRS detection using integrated variance for ECG gated cardiac MRI
  55. Preprocessing of unipolar signals acquired by a novel intracardiac mapping system
  56. In-vitro experiments to characterize ventricular electromechanics
  57. Continuous non-invasive monitoring of blood pressure in the operating room: a cuffless optical technology at the fingertip
  58. Application of microwave sensor technology in cardiovascular disease for plaque detection
  59. Artificial blood circulatory and special Ultrasound Doppler probes for detecting and sizing gaseous embolism
  60. Detection of microsleep events in a car driving simulation study using electrocardiographic features
  61. A method to determine the kink resistance of stents and stent delivery systems according to international standards
  62. Comparison of stented bifurcation and straight vessel 3D-simulation with a prior simulated velocity profile inlet
  63. Transient Euler-Lagrange/DEM simulation of stent thrombosis
  64. Automated control of the laser welding process of heart valve scaffolds
  65. Automation of a test bench for accessing the bendability of electrospun vascular grafts
  66. Influence of storage conditions on the release of growth factors in platelet-rich blood derivatives
  67. Cryopreservation of cells using defined serum-free cryoprotective agents
  68. New bioreactor vessel for tissue engineering of human nasal septal chondrocytes
  69. Determination of the membrane hydraulic permeability of MSCs
  70. Climate retainment in carbon dioxide incubators
  71. Multiple factors influencing OR ventilation system effectiveness
  72. Evaluation of an app-based stress protocol
  73. Medication process in Styrian hospitals
  74. Control tower to surgical theater
  75. Development of a skull phantom for the assessment of implant X-ray visibility
  76. Surgical navigation with QR codes
  77. Investigation of the pressure gradient of embolic protection devices
  78. Computer assistance in femoral derotation osteotomy: a bottom-up approach
  79. Automatic depth scanning system for 3D infrared thermography
  80. A service for monitoring the quality of intraoperative cone beam CT images
  81. Resectoscope with an easy to use twist mechanism for improved handling
  82. In vitro simulation of distribution processes following intramuscular injection
  83. Adjusting inkjet printhead parameters to deposit drugs into micro-sized reservoirs
  84. A flexible standalone system with integrated sensor feedback for multi-pad electrode FES of the hand
  85. Smart control for functional electrical stimulation with optimal pulse intensity
  86. Tactile display on the remaining hand for unilateral hand amputees
  87. Effects of sustained electrical stimulation on spasticity assessed by the pendulum test
  88. An improved tracking framework for ultrasound probe localization in image-guided radiosurgery
  89. Improvement of a subviral particle tracker by the use of a LAP-Kalman-algorithm
  90. Learning discriminative classification models for grading anal intraepithelial neoplasia
  91. Regularization of EIT reconstruction based on multi-scales wavelet transforms
  92. Assessing MRI susceptibility artefact through an indicator of image distortion
  93. EyeGuidance – a computer controlled system to guide eye movements
  94. A framework for feedback-based segmentation of 3D image stacks
  95. Doppler optical coherence tomography as a promising tool for detecting fluid in the human middle ear
  96. 3D Local in vivo Environment (LivE) imaging for single cell protein analysis of bone tissue
  97. Inside-Out access strategy using new trans-vascular catheter approach
  98. US/MRI fusion with new optical tracking and marker approach for interventional procedures inside the MRI suite
  99. Impact of different registration methods in MEG source analysis
  100. 3D segmentation of thyroid ultrasound images using active contours
  101. Designing a compact MRI motion phantom
  102. Cerebral cortex classification by conditional random fields applied to intraoperative thermal imaging
  103. Classification of indirect immunofluorescence images using thresholded local binary count features
  104. Analysis of muscle fatigue conditions using time-frequency images and GLCM features
  105. Numerical evaluation of image parameters of ETR-1
  106. Fabrication of a compliant phantom of the human aortic arch for use in Particle Image Velocimetry (PIV) experimentation
  107. Effect of the number of electrodes on the reconstructed lung shape in electrical impedance tomography
  108. Hardware dependencies of GPU-accelerated beamformer performances for microwave breast cancer detection
  109. Computer assisted assessment of progressing osteoradionecrosis of the jaw for clinical diagnosis and treatment
  110. Evaluation of reconstruction parameters of electrical impedance tomography on aorta detection during saline bolus injection
  111. Evaluation of open-source software for the lung segmentation
  112. Automatic determination of lung features of CF patients in CT scans
  113. Image analysis of self-organized multicellular patterns
  114. Effect of key parameters on synthesis of superparamagnetic nanoparticles (SPIONs)
  115. Radiopacity assessment of neurovascular implants
  116. Development of a desiccant based dielectric for monitoring humidity conditions in miniaturized hermetic implantable packages
  117. Development of an artifact-free aneurysm clip
  118. Enhancing the regeneration of bone defects by alkalizing the peri-implant zone – an in vitro approach
  119. Rapid prototyping of replica knee implants for in vitro testing
  120. Protecting ultra- and hyperhydrophilic implant surfaces in dry state from loss of wettability
  121. Advanced wettability analysis of implant surfaces
  122. Patient-specific hip prostheses designed by surgeons
  123. Plasma treatment on novel carbon fiber reinforced PEEK cages to enhance bioactivity
  124. Wear of a total intervertebral disc prosthesis
  125. Digital health and digital biomarkers – enabling value chains on health data
  126. Usability in the lifecycle of medical software development
  127. Influence of different test gases in a non-destructive 100% quality control system for medical devices
  128. Device development guided by user satisfaction survey on auricular vagus nerve stimulation
  129. Empirical assessment of the time course of innovation in biomedical engineering: first results of a comparative approach
  130. Effect of left atrial hypertrophy on P-wave morphology in a computational model
  131. Simulation of intracardiac electrograms around acute ablation lesions
  132. Parametrization of activation based cardiac electrophysiology models using bidomain model simulations
  133. Assessment of nasal resistance using computational fluid dynamics
  134. Resistance in a non-linear autoregressive model of pulmonary mechanics
  135. Inspiratory and expiratory elastance in a non-linear autoregressive model of pulmonary mechanics
  136. Determination of regional lung function in cystic fibrosis using electrical impedance tomography
  137. Development of parietal bone surrogates for parietal graft lift training
  138. Numerical simulation of mechanically stimulated bone remodelling
  139. Conversion of engineering stresses to Cauchy stresses in tensile and compression tests of thermoplastic polymers
  140. Numerical examinations of simplified spondylodesis models concerning energy absorption in magnetic resonance imaging
  141. Principle study on the signal connection at transabdominal fetal pulse oximetry
  142. Influence of Siluron® insertion on model drug distribution in the simulated vitreous body
  143. Evaluating different approaches to identify a three parameter gas exchange model
  144. Effects of fibrosis on the extracellular potential based on 3D reconstructions from histological sections of heart tissue
  145. From imaging to hemodynamics – how reconstruction kernels influence the blood flow predictions in intracranial aneurysms
  146. Flow optimised design of a novel point-of-care diagnostic device for the detection of disease specific biomarkers
  147. Improved FPGA controlled artificial vascular system for plethysmographic measurements
  148. Minimally spaced electrode positions for multi-functional chest sensors: ECG and respiratory signal estimation
  149. Automated detection of alveolar arches for nasoalveolar molding in cleft lip and palate treatment
  150. Control scheme selection in human-machine- interfaces by analysis of activity signals
  151. Event-based sampling for reducing communication load in realtime human motion analysis by wireless inertial sensor networks
  152. Automatic pairing of inertial sensors to lower limb segments – a plug-and-play approach
  153. Contactless respiratory monitoring system for magnetic resonance imaging applications using a laser range sensor
  154. Interactive monitoring system for visual respiratory biofeedback
  155. Development of a low-cost senor based aid for visually impaired people
  156. Patient assistive system for the shoulder joint
  157. A passive beating heart setup for interventional cardiology training
Sign up now to receive a 20% welcome discount
Institutional Access
How does access work?
Have an idea on how to improve our website?
Please write us.
© 2025 De Gruyter Brill
Downloaded on 15.9.2025 from https://www.degruyterbrill.com/document/doi/10.1515/cdbme-2016-0134/html
Scroll to top button