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https://www.readbyqxmd.com/read/28220362/the-role-of-impedance-planimetry-in-the-evaluation-of-esophageal-disorders
#1
REVIEW
Nitin K Ahuja, John O Clarke
PURPOSE OF REVIEW: Impedance planimetry measures tissue wall distensibility as a function of pressure and cross-sectional area. Recent interest in this technique's relevance to the gastrointestinal tract has been accelerated by the availability of the functional lumen imaging probe, a catheter-based system that dynamically quantitates these biomechanical properties. Herein, we review the device's particular utility in the setting of esophageal pathology, including processes affecting the esophageal body as well as the upper and lower esophageal sphincters...
February 2017: Current Gastroenterology Reports
https://www.readbyqxmd.com/read/28185360/effect-of-environmental-impedance-surrounding-a-radiofrequency-ablation-catheter-electrode-on-lesion-characteristics
#2
Duy T Nguyen, Kianna Nguyen, Lijun Zheng, Joseph Schuller, Matthew Zipse, Wendy S Tzou, William H Sauer
INTRODUCTION: The electrical conductivity of the environment surrounding a catheter electrode may affect radiofrequency (RF) current. A higher impedance environment enveloping a catheter tip can be insulating and thus direct RF preferentially into targeted cardiac tissue. We sought to evaluate whether different environmental impedances will affect RF lesions. METHODS: An ex vivo model using bovine myocardium, load cell, and 4 mm ablation catheter was tested using a circulating bath of normal (0...
February 10, 2017: Journal of Cardiovascular Electrophysiology
https://www.readbyqxmd.com/read/28167080/epicardial-catheter-ablation-of-ventricular-tachycardia
#3
REVIEW
Arash Aryana, André d'Avila
Over the last two decades, epicardial catheter ablation has evolved into a practical approach for treatment of ventricular tachycardia (VT). There are certain considerations when performing this procedure. First, presence of epicardial fat can diminish peak-to-peak electrogram amplitude and also impede radiofrequency energy delivery. Hence, epicardial VT ablation should be performed with cooled-tip radiofrequency using reduced irrigation flow within a relatively 'dry' pericardial milieu. Furthermore, catheter orientation is key when performing epicardial ablation...
March 2017: Cardiac Electrophysiology Clinics
https://www.readbyqxmd.com/read/28113280/miniaturizing-floating-traps-to-increase-rf-safety-of-magnetic-resonance-guided-percutaneous-procedures
#4
Gregory Griffin, Kevan Anderson, Graham Wright
OBJECTIVE: MRI in the area of cardiovascular catheter-based interventional procedures is an active field. A common intervention - revascularization of chronic total occlusions, requires a conductive guidewire for revascularization. The mechanical properties of guidewires are paramount to the successful execution of such procedures. Furthermore to benefit from MRI techniques, additional conductors are required to transmit signal from the tip of a catheter. Long thin conductors in MRI systems pose a safety risk in the form of RF heating due to induced RF currents on the conductors...
April 20, 2016: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28113187/miniaturizing-floating-traps-to-increase-rf-safety-of-magnetic-resonance-guided-percutaneous-procedures
#5
Gregory H Griffin, Kevan J T Anderson, Graham A Wright
OBJECTIVE: MRI in the area of cardiovascular catheter-based interventional procedures is an active field. A common intervention-revascularization of chronic total occlusions, requires a conductive guidewire for revascularization. The mechanical properties of guidewires are paramount to the successful execution of such procedures. Furthermore to benefit from MRI techniques, additional conductors are required to transmit signal from the tip of a catheter. Long thin conductors in MRI systems pose a safety risk in the form of RF heating due to induced RF currents on the conductors...
February 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28104089/prediction-of-radiofrequency-ablation-lesion-formation-using-a-novel-temperature-sensing-technology-incorporated-in-a-force-sensing-catheter
#6
Guy Rozen, Leon Ptaszek, Israel Zilberman, Kevin Cordaro, E Kevin Heist, Christopher Beeckler, Andres Altmann, Zhang Ying, Zhenjiang Liu, Jeremy N Ruskin, Assaf Govari, Moussa Mansour
BACKGROUND: Real-time radiofrequency (RF) ablation lesion assessment is a major unmet need in cardiac electrophysiology. OBJECTIVE: The purpose of this study was to assess whether improved temperature measurement using a novel thermocoupling (TC) technology combined with information derived from impedance change, contact force (CF) sensing, and catheter orientation allows accurate real-time prediction of ablation lesion formation. METHODS: RF ablation lesions were delivered in the ventricles of 15 swine using a novel externally irrigated-tip catheter containing 6 miniature TC sensors in addition to force sensing technology...
February 2017: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/28064250/novel-method-for-electrode-tissue-contact-measurement-with-multi-electrode-catheters
#7
René van Es, John Hauck, Vincent Jhm van Driel, Kars Neven, Harry van Wessel, Pieter A Doevendans, Fred Hm Wittkampf
AIMS: With multi-electrode catheters, measuring contact force (CF) on each electrode is technically challenging. Present electrical methods, like the electrical coupling index (ECI) may yield false positive values in pulmonary veins. We developed a novel method that measures electrode-interface resistance (IR) by applying a very local electrical field between neighbouring catheter electrodes while measuring voltage between each catheter electrode and a skin patch. The aim of this study was to evaluate the new IR method to measure electrode-tissue contact...
January 6, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/28004408/ten-year-clinical-experience-with-the-lumenless-catheter-delivered-4-1-fr-diameter-pacing-lead-in-patients-with-and-without-congenital-heart
#8
Neha Bansal, Sharmeen Samuel, Kathleen Zelin, Peter P Karpawich
BACKGROUND: Patients with congenital heart defects (CHD) often present more challenges to pacing therapy due to anatomy than those without CHD. The lumenless, 4.1Fr diameter M3830 pacing lead (Medtronic, Inc., Minneapolis, MN, USA), approved for use in 2005, has, to date, reported to have excellent short-term (<6 years) lead performance. Unfortunately, very long-term performance is unknown, especially among CHD patients and with implants at alternate pacing (AP) sites. This study reports a 10-year clinical experience with the M3830 lead...
January 2017: Pacing and Clinical Electrophysiology: PACE
https://www.readbyqxmd.com/read/27996100/complications-with-the-micra-tps-pacemaker-system-persistent-complete-heart-block-and-late-capture-failure
#9
Niels Holm, Andreas Müller, Rainer Zbinden
A Medtronic MICRA transcatheter pacing system (Medtronic, Minneapolis, MN, USA) was implanted in an 86-year-old patient with sick sinus syndrome and left bundle branch block after transfemoral aortic valve implantation. During implantation she developed a persistent complete heart block due to manipulation with the large-bore delivery catheter. Two weeks later, acute pacemaker dysfunction occurred due to massive increase of pacing threshold and impedance without obvious pacemaker dislocation or myocardial perforation...
December 20, 2016: Pacing and Clinical Electrophysiology: PACE
https://www.readbyqxmd.com/read/27979491/postoperative-urinary-retention-in-colorectal-surgery-within-an-enhanced-recovery-pathway
#10
Fabian Grass, Juliette Slieker, Pierre Frauche, Josep Solà, Catherine Blanc, Nicolas Demartines, Martin Hübner
BACKGROUND: Enhanced recovery after surgery (ERAS) guidelines for colorectal surgery suggest routine transurethral bladder drainage with early removal to prevent urinary tract infection (UTI). The aim of this study was to identify risk factors for urinary retention (UR). METHODS: This retrospective analysis included all colorectal patients since ERAS implementation in May 2011-November 2014. From the prospective ERAS database, over 100 items related to demographics, surgery, compliance, and outcome were analyzed...
January 2017: Journal of Surgical Research
https://www.readbyqxmd.com/read/27943352/electrode-contact-force-controlled-bipolar-radiofrequency-ablation-different-effects-on-lesion-size-between-dual-and-single-bath-preparations
#11
Masaomi Chinushi, Osamu Saitoh, Junya Watanabe, Ayari Sugai, Katsuya Suzuki, Yukio Hosaka, Hiroshi Furushima
BACKGROUND: During bipolar (BIP) radiofrequency (RF) ablation using two catheters in humans, each catheter is placed in separate cardiac chambers or spaces. We developed a contact force-controlled experimental preparation, and compared measurements made with two catheters placed in a single bath (SB), versus each catheter placed in separate baths, in order to assess the preparation-dependent differences in the results of BIP-RF ablation. METHODS: In the SB experiments, a porcine heart was placed in the center of the bath, while in the dual-bath (DB) experiments, it was placed between two half baths communicating through windows...
March 2017: Pacing and Clinical Electrophysiology: PACE
https://www.readbyqxmd.com/read/27920480/comparison-of-multichannel-intraluminal-impedance-ph-monitoring-and-reflux-scintigraphy-in-pediatric-patients-with-suspected-gastroesophageal-reflux
#12
Nuray Uslu Kızılkan, Murat Fani Bozkurt, Inci Nur Saltık Temizel, Hülya Demir, Aysel Yüce, Biray Caner, Hasan Özen
AIM: To evaluate the agreement of multichannel intraluminal impedance-pH monitoring (MII-pHM) and gastroesophageal reflux scintigraphy (GES) for the diagnosis of gastroesophageal reflux disease. METHODS: Seventy-five consecutive patients with suspected gastroesophageal reflux disease (GERD) underwent 24-h combined MII-pHM recording and one hour radionuclide scintigraphy during the course of the MII-pHM study. Catheters with 6 impedance channels and 1 pH sensor were placed transnasally...
November 21, 2016: World Journal of Gastroenterology: WJG
https://www.readbyqxmd.com/read/27909471/contact-force-and-atrial-fibrillation-ablation
#13
REVIEW
Ullah W, Schilling Rj, Wong T
Catheters able to measure the force and vector of contact between the catheter tip and myocardium are now available. Pre-clinical work has established that the degree of contact between the radiofrequency ablation catheter and myocardium correlates with the size of the delivered lesion. Excess contact is associated with steam pops and perforation. Catheter contact varies within the left atrium secondary to factors including respiration, location, atrial rhythm and the trans-septal catheter delivery technology used...
February 2016: Journal of Atrial Fibrillation
https://www.readbyqxmd.com/read/27789351/cu-blood-flow-model-through-a-catheterized-mild-stenotic-artery-with-a-thrombosis
#14
Thanaa Elnaqeeb, Khaled S Mekheimer, Felwah Alghamdi
Copper nanoparticles blood flow analysis through a catheterized mild stenotic artery with a thrombosis is presented. The system of coupled governing equations are prescribed and then simplified under mild stenosis assumptions. The governing equations are solved exactly, and then expressions for temperature, axial velocity, stream function, wall shear stress and resistance impedance are obtained generally for metallic nanoparticles blood flow. Due to the importance of copper nanoparticles in biomedicine, the results for Cu-blood flow model are introduced...
December 2016: Mathematical Biosciences
https://www.readbyqxmd.com/read/27788384/blood-vessel-modeling-for-interactive-simulation-of-interventional-neuroradiology-procedures
#15
E Kerrien, A Yureidini, J Dequidt, C Duriez, R Anxionnat, S Cotin
Endovascular interventions can benefit from interactive simulation in their training phase but also during pre-operative and intra-operative phases if simulation scenarios are based on patient data. A key feature in this context is the ability to extract, from patient images, models of blood vessels that impede neither the realism nor the performance of simulation. This paper addresses both the segmentation and reconstruction of the vasculature from 3D Rotational Angiography data, and adapted to simulation: An original tracking algorithm is proposed to segment the vessel tree while filtering points extracted at the vessel surface in the vicinity of each point on the centerline; then an automatic procedure is described to reconstruct each local unstructured point set as a skeleton-based implicit surface (blobby model)...
October 14, 2016: Medical Image Analysis
https://www.readbyqxmd.com/read/27778419/baseline-impedance-measured-during-high-resolution-esophageal-impedance-manometry-reliably-discriminates-gerd-patients
#16
K Ravi, D M Geno, M F Vela, M D Crowell, D A Katzka
BACKGROUND: Baseline impedance measured with ambulatory impedance pH monitoring (MII-pH) and a mucosal impedance catheter detects gastroesophageal reflux disease (GERD). However, these tools are limited by cost or patient tolerance. We investigated whether baseline impedance measured during high-resolution impedance manometry (HRIM) distinguishes GERD patients from controls. METHODS: Consecutive patients with clinical HRIM and MII-pH testing were identified. Gastroesophageal reflux disease was defined by esophageal pH <4 for ≥5% of both the supine and total study time, whereas controls had an esophageal pH <4 for ≤3% of the study performed off PPI...
October 24, 2016: Neurogastroenterology and Motility: the Official Journal of the European Gastrointestinal Motility Society
https://www.readbyqxmd.com/read/27773967/ultrasonic-transducer-guided-electrochemical-impedance-spectroscopy-to-assess-lipid-laden-plaques
#17
Jianguo Ma, Yuan Luo, René R Sevag Packard, Teng Ma, Yichen Ding, Parinaz Abiri, Yu-Chong Tai, Qifa Zhou, Kirk K Shung, Rongsong Li, Tzung Hsiai
Plaque rupture causes acute coronary syndromes and stroke. Intraplaque oxidized low density lipoprotein (oxLDL) is metabolically unstable and prone to induce rupture. We designed an intravascular ultrasound (IVUS)-guided electrochemical impedance spectroscopy (EIS) sensor to enhance the detection reproducibility of oxLDL-laden plaques. The flexible 2-point micro-electrode array for EIS was affixed to an inflatable balloon anchored onto a co-axial double layer catheter (outer diameter = 2 mm). The mechanically scanning-driven IVUS transducer (45 MHz) was deployed through the inner catheter (diameter = 1...
November 1, 2016: Sensors and Actuators. B, Chemical
https://www.readbyqxmd.com/read/27754040/os-13-06-generation-of-aortic-flow-velocity-from-derived-aortic-pressure-waveforms-using-age-specific-aortic-impedance-modelling
#18
Audrey Adji, Thomas Weber, Caroline O'Brien, Michael O'Rourke, Alberto Avolio
OBJECTIVE: Relative ease of estimating of Ascending Aortic (AA) pressure non-invasively enables interpretation of age-related pressure waveform changes due to altered pulse wave propagation. AA flow velocity waveforms, measured invasively by ElectroMagnetic (EM) cuff/ catheter, and non-invasively by Cardiac Magnetic Resonance (CMR) also show characteristic aging changes attributable to aortic dilation and subtle impairment of Left Ventricular (LV) function. Conventional Doppler waveforms do not...
September 2016: Journal of Hypertension
https://www.readbyqxmd.com/read/27738965/how-to-optimally-apply-impedance-in-the-evaluation-of-esophageal-dysmotility
#19
REVIEW
Amit Patel, C Prakash Gyawali
The utilization of impedance technology has enhanced our understanding and assessment of esophageal dysmotility. Esophageal high-resolution manometry (HRM) catheters incorporated with multiple impedance electrodes help assess esophageal bolus transit, and the combination is termed high-resolution impedance manometry (HRIM). Novel metrics have been developed with HRIM-including esophageal impedance integral ratio, bolus flow time, nadir impedance pressure, and impedance bolus height-that augments the assessment of esophageal bolus transit...
November 2016: Current Gastroenterology Reports
https://www.readbyqxmd.com/read/27702853/left-atrial-model-reconstruction-in-atrial-fibrillation-ablation-reliability-of-new-mapping-and-complex-impedance-systems
#20
Aldo Bonso, Mauro Fantinel, Giovanna Scalchi, Sabrina Ferrara, Stefano Indiani, Federico Calore, Claudia Licciardello
AIMS: The effectiveness of atrial fibrillation (AF) ablation relies on detailed knowledge of the anatomy of the left atrium (LA) and pulmonary veins (PVs). It is common to combine computed tomography/magnetic resonance (CT/MR) with imaging by electroanatomical (EA) mapping systems. The aim of this study was to evaluate the accuracy of LA anatomical reconstruction by 'One Model' and 'VeriSense' tools (Ensite Velocity 3.0, St Jude Medical), compared with CT/MR imaging. METHODS AND RESULTS: Seventy-two patients with AF underwent pre-procedural imaging (97% CT-scan, 3% MR imaging) and transcatheter ablation of PVs...
October 4, 2016: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
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