Irrigation did not prevent interfacial boiling, which occurred during uninterrupted radiofrequency energy deposition and lesion growth. The mechanism underlying the larger lesion was delay or inhibition of impedance rise this was associated with attenuation or prevention of electrode coagulum. Ablation during electrode irrigation with normal saline was associated with greater ablation energy deposition and larger lesion dimensions than non-irrigated ablation. Intramyocardial temperatures predicted by each model were correlated with corresponding temperatures measured in vitro. interfacial temperature measured in vitro. electrode temperature measured in vitro 2. Two models were constructed, each utilizing a different core assumption regarding the electrode-tissue boundary: 1. Finite element simulations of myocardial temperature during irrigated ablation were performed to further elucidate irrigation biophysics and provide a more detailed myocardial temperature profile. Blood flow velocities assessed were 0 and 0.26 m/s. Irrigant flow rates assessed were 20 and 100 cc/min. Irrigants assessed were room temperature normal saline, iced normal saline, and dextrose. Electrode, electrode-endocardial interface, and intramyocardial temperatures were assessed, as were ablation circuit impedance, total delivered energy, and lesion and electrode morphology. Ablation with and without electrode irrigation was performed in vitro utilizing a whole blood-superfused system. To assess the influence of irrigant rate, composition, temperature and blood flow velocity. PURPOSE: To examine the biophysics of irrigated ablation by correlating electrode and myocardial temperatures with ablation circuit impedance and lesion morphology, and to perform a comparison with non-irrigated ablation modes. It has been suggested that maximal myocardial temperature is shifted deep into myocardium during irrigated ablation. In the future the scalability of the EPS will allow the implementation of a whole head ultra-dense EPS array.īACKGROUND: Previous reports have proposed that prevention of electrode-endocardial interfacial boiling is the key mechanism by which radiofrequency application using an irrigated electrode yields a larger ablation lesion than a non-irrigated electrode. CONCLUSIONS: The EPS provides a promising alternative with many added benefits compared to standard EEG sensors, including reduced setup time and elimination of sensor cross-coupling. COMPARISON WITH EXISTING METHOD(S): These studies comprised measurements of both free running EEG and Event Related Potentials (ERPs) from a commercial EEG system and EPS. RESULTS: Quantitatively, highly similar signals were observed between the EPS and EEG sensors for both free running and evoked brain activity with cross correlations of higher than 0.9 between the EPS and a standard benchmark EEG system. A comprehensive study was undertaken to compare neural signals recorded by the EPS with a standard commercial EEG system. The absence of 1/f noise makes the EPS ideal for use with signal frequencies of â❁0Hz or less. The EPS is a novel active ultrahigh impedance capacitively coupled sensor. NEW METHOD: In order to tackle these issues a prototype Electric Potential Sensor (EPS) device based on an auto-zero operational amplifier was developed and evaluated. Although reliable, these electrodes have multiple drawbacks: they suffer from noise, such as offset potential drift, and usability issues, for example, difficult skin preparation and cross-coupling of adjacent electrodes. Ag/AgCl metal electrodes have been the gold standard for non-invasively monitoring electrical brain activity. BACKGROUND: Electroencephalography (EEG) is still a widely used imaging tool that combines high temporal resolution with a relatively low cost.
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