Refine
Year of publication
Document Type
- Conference Proceeding (69)
- Article (reviewed) (14)
- Patent (11)
- Contribution to a Periodical (6)
- Article (unreviewed) (2)
Conference Type
- Konferenz-Abstract (53)
- Konferenzartikel (12)
- Konferenz-Poster (4)
Language
- English (76)
- German (24)
- Other language (1)
- Multiple languages (1)
Has Fulltext
- no (102) (remove)
Is part of the Bibliography
- yes (102)
Keywords
- CST (7)
- HF-Ablation (7)
- Herzrhythmusmodell (6)
- CRT (5)
- Heart rhythm model (5)
- Herzkrankheit (5)
- Modeling and simulation (5)
- Synchronisierung (4)
- Cardiac resynchronization therapy (3)
- Herzschrittmacher (3)
Institute
Open Access
- Open Access (65)
- Closed Access (29)
- Bronze (4)
- Closed (2)
Cardiac resynchronization therapy (CRT) with hemodynamic optimized biventricular pacing is an established therapy for heart failure patients with sinus rhythm, reduced left ventricular ejection fraction and wide QRS complex. The aim of the study was to evaluate electrical right and left cardiac atrioventricular delay and left atrial delay in CRT responder and non-responder with sinus rhythm.
Methods: Heart failure patients with New York Heart Association class 3.0 ± 0.3, sinus rhythm and 27.7 ± 6.1% left ventricular ejection fraction were measured by surface ECG and transesophageal bipolar left atrial and left ventricular ECG before implantation of CRT devices. Electrical right cardiac atrioventricular delay was measured between onset of P wave and onset of QRS complex in the surface ECG, left cardiac atrioventricular delay between onset of left atrial signal and onset of left ventricular signal in the transesophageal ECG and left atrial delay between onset and offset of left atrial signal in the transesophageal ECG.
Results: Electrical atrioventricular and left atrial delay were 196.9 ± 38.7 ms right and 194.5 ± 44.9 ms left cardiac atrioventricular delay, and 47.7 ± 13.9 ms left atrial delay. There were positive correlation between right and left cardiac atrioventricular delay (r = 0.803 P < 0.001) and negative correlation between left atrial delay and left ventricular ejection fraction (r = −0.694 P = 0.026) with 67% CRT responder.
Conclusions: Transesophageal electrical left cardiac atrioventricular delay and left atrial delay may be useful preoperative atrial desynchronization parameters to improve CRT optimization.
The high frequency (HF) catheter ablation is the gold standard for the therapy of many cardiac tachyarrhythmias, such as atrioventricular node re-entry tachycardia (AVNRT), atrioventricular re-entry tachycardia (AVRT) or atrial flutter (AFL). The aim of the study was to simulate the HF ablation of AVNRT, AVRT, AFL and its heat propagation in reference to the supplied power with different electrode material and electrode size. The modeling and simulation were performed with the thermal and electromagnetic simulation software CST® (Computer Simulation Technology, Darmstadt). The modeling and simulation were carried out using ablation catheters with 4 mm tip electrode and 8 mm tip electrode with different electrode materials. Both electrode types were made of platinum and gold respectively. For the measurement of the heat propagation in the heart tissue, the catheters were integrated in the Offenburg heart rhythm model. The HF ablation procedures were performed with the 4 mm platinum tip electrode, with an application duration of 45 seconds and a power output of 40 watts. The HF ablation of the atrioventricular node slow pathway produced a maximum temperature of 66.33 °C. The Kent bundle HF ablation in the left atrium achieved a maximum temperature of 67.14 °C. The HF ablation of the right atrial isthmus resulted 65.96 °C. The 8 mm distal platinum tip electrode and a power output of 60 watts reached 72.85 °C. The 8 mm distal gold tip electrode and a power output of 60 watt reached 64.66 °C, due to the improved thermal conductivity of gold. Virtual heart and ablation electrode models allow the static and dynamic simulation of HF ablation with different electrode material and electrode size. The 3D simulation of the temperature profile may be used to optimize the AVNRT, AVRT and AFL HF ablation.
Die Katheterablation mit Hochfrequenzstrom (HF) ist der Goldstandard für die Therapie vieler kardi-aler Tachyarrhythmien. Bei der HF-Ablation entstehen Temperaturen zwischen 50 °C und 70 °C, wo-durch bestimmte Strukturen im Herzgewebe gezielt zerstört werden können. Ziel der Studie ist, die HF-Ablation und deren Wärmeausbreitung in Bezug auf die zugeführte Leistung mit unterschiedli-chem Elektrodenmaterial und Elektrodengröße bei supraventrikülären Tachykardien zu simulieren.
Background: The application of high-frequency ablation is used for the treatment of tachycardia arrhythmias and is a respected method. Ablation with high frequency current leads to the targeted heat destruction of myocardial tissue at specific sites and thus prevents the pathological propagation of excitation through these structures.
Purpose: The aim of this study was to simulate heat propagation during RF ablation with modeled electrodes in different sizes and materials. The simulation was performed on atrioventricular node re-entry tachycardia (AVNRT), atrioventricular re-entry tachycardia (AVRT) and atrial flutter (AFL).
Methods: Using the modeling and simulation software CST, ablation catheters with 4 mm and 8 mm tip electrodes were modeled from gold and platinum for each. The designed catheters correspond to the manufacturer"s specifications of Medtronic, Biotronik and Osypka. The catheters were integrated into the Offenburg heart rhythm model to simulate and compare the heat propagation during an ablation application, which also takes into account the blood flow in the four heart chambers. A power of 5 W - 40 W was simulated for the 4 mm electrodes and a power of 50 W - 80 W for the 8 mm electrodes.
Results: During the simulated HF ablation application, the temperature at the ablation electrode was measured at different powers. This is 40.67°C at 5 W, 44.34°C at 10 W, 51.76°C at 20 W, 59.0°C at 30 W, and 66.33°C at 40 W. The measured temperature during 40 W application is 39.5°C at 0,5 mm depth in the myocardium and 37.5°C at 2 mm depth.
In the simulation, the 8 mm platinum electrode reached an ablation temperature of 72.85°C at its tip during an applied power of 60 W. In contrast, the 8 mm platinum electrode reached a depth of 5 mm at 39.5 C° and at a depth of 2 mm at 37.5 °C. In contrast, the 8 mm gold electrode reached a temperature of 64.66°C with the same performance. This is due to the thermal properties of gold, which has a better thermal conductivity than platinum.
Conclusions: CST offers the possibility to carry out a static and dynamic simulation of a heart model and the ablation electrodes integrated in it during an HF ablation. In variation with different electrode sizes and materials, therapy methods for the treatment of AVNRT, AVRT and AFL can be optimized
Electrode modelling and simulation of diagnostic and pulmonary vein isolation in atrial fibrillation
(2022)
In cardiac resynchronization therapy (CRT) for heart failure, individualization of the AV delay is essential to improve hemodynamics and to minimize non-responder rate. In patients in sinus rhythm having additional disposition to bradycardia, optimization is necessary for both situations, atrial sensing and pacing. Therefore, echo-optimization is the goldstandard but time consuming. Unfortunately, it depends on the particular CRT systems parameter set if the resulting individually optimal AV delays can be programmed or not. Some CRT systems provide a set of AV delays for DDD operation combined with a set of the pace-sense-compensation to optimize the AV delay in DDD and VDD operation. The pace-sense-compensation (PSC) can be defined by the difference of implant-related interatrial conduction intervals in DDD and VDD operation measured in the esophageal left atrial electrogram. In a cohort of 96 CRT patients we found mean PSC of 59-35ms ranging between 0-143ms. As a consequence, allowing 10ms tolerance, AVD optimization is completely impossible in one of the two modes, VDD or DDD operation, in 34 (35%) or 5 (5%) patients with implants restricting the PSC range to 60ms or 100ms, respectively. Thus, we propose companies to provide CRT systems with programmable pace-sense- compensation between 0ms and 150ms.
Abstract: Electric field of biventricular (BV) pacing, left ventricular (LV) electrode position and electrical interventricular desynchronization are important parameters for successful cardiac resynchronization therapy (CRT) in patients with heart failure, sinus rhythm and reduced LV ejection fraction. The aim of the study was to evaluate electric pacing field of transesophageal left atrial (LA) pacing and BV pacing with 3D heart rhythm simulation. Bipolar right atrial (RA), right ventricular (RV), LV electrodes and multipolar hemispherical esophageal LA electrodes were modeled with CST (Computer Simulation Technology, Darmstadt). Electric pacing field were simulated with bipolar RA and RV pacing with Solid S (Biotronik) electrode, bipolar LV pacing with Attain 4194 (Medtronic) electrode and bipolar LA pacing with TO8 (Osypka) esophageal electrode. 3D heart rhythm model with esophagus allowed electric pacing field simulation of 4-chamber pacing with bipolar intracardiac RA, RV, LV pacing and bipolar transesophageal LA pacing. The pacing amplitudes were 3V RA pacing amplitude, 50V LA pacing amplitude, 1.5V RV pacing amplitude and 3V LV pacing amplitude with 0.5ms pacing pulse duration. The atrioventricular delay between RA pacing and BV pacing was 140ms atrioventricular pacing delay and simultaneous RV and LV pacing. Electric pacing fields were simulated during the different pacing modes AAI, VVI, DDD and DDD0V. The intracardiac far-field pacing potentials were evaluated with intracardiac electrodes and a distance of 1mm from the electrodes with RA electrode 1.104V, RV electrode 0.703V and LV electrode 1.32V. The transesophageal far-field pacing potential was evaluated with transesophageal electrode and a distance of 10mm from the elelctrode with LA electrode 6.076V. Heart rhythm model simulation with esophagus allows evaluation of electric pacing fields in AAI, VVI, DDD, DDD0V and DDD0D pacing modes. Electric pacing field of RA, RV and LV pacing in combination with LA pacing may additional useful pacing mode in CRT non-responders.
Background: Transesophageal left atrial (LA) pacing and transesophageal LA ECG recording are semi-invasive techniques for diagnostic and therapy of supraventricular rhythm disturbance. Cardiac resynchronization therapy (CRT) with right atrial (RA) sensed biventricular pacing is an established therapy for heart failure patients with reduced left ventricular (LV) ejection fraction, sinus rhythm and interventricular electrical desynchronization.
Purpose: The aim of the study was to evaluate electromagnetic and voltage pacing fields of the combination of RA pacing, LA pacing and biventricular pacing in patients with long interatrial and interventricular electrical desynchronization.
Methods: The modelling and electromagnetic simulations of transesophageal LA pacing in combination with RA pacing and biventricular pacing would be staged and analyzed with the CST (Computer Simulation Technology) software. Different electrodes were modelled in order to simulate different types of bipolar pacing in the 3D-CAD Offenburg heart rhythm model: The bipolar Solid S (Biotronik) electrode where modelled for RA pacing and right ventricular (RV) pacing, Attain 4194 (Medtronic) for LV pacing and TO8 (Osypka) multipolar esophageal electrode with hemispheric electrodes for LA pacing.
Results: The pacemaker amplitudes for the electromagnetic pacing simulations were performed with 3 V for RA pacing, 1.5 V for RV pacing, 50 V for LA pacing and 3V for LV pacing with pacing impulse duration of 0.5 ms for RA, RV and LV pacing and 10 ms for LA pacing. The atrioventricular pacing delay after RA pacing was 140 ms. The different pacing modes AAI, VVI, DDD, DDD0V and DDD0D were evaluated for the analysis of the electric pacing field propagation of pacemaker, CRT and LA pacing. The pacing results were compared at minimum (LOW) and maximum (HIGH) parameter settings. While the LOW setting produced fewer tetrahedral and more inaccurate results, the HIGH setting produced many tetrahedral and therefore more accurate results.
Conclusions: The simulation of the combination of transesophageal LA pacing with RA sensed biventricular pacing is possible with the Offenburg heart rhythm model. The new temporary 4-chamber pacing method may be additional useful method in CRT non-responders with long interatrial electrical delay.