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https://www.readbyqxmd.com/read/29149500/ep-radiofrequency-generators-significant-offsets-between-selected-and-delivered-power
#1
Felix Bourier, Bernhard Schwarz, Amir Brkic, Lara Wolf, Verena Semmler, Marc Kottmaier, Elena Risse, Marta Telishevska, Stephanie Brooks, Sarah Lengauer, Marielouise Kornmayer, Katharina Koch-Büttner, Florian Berger, Gabriele Hessling, Isabel Deisenhofer, Tilko Reents
INTRODUCTION: For radiofrequency ablation, the EP Shuttle®, Ampere®, and SmartAblate® generator models are most frequently used in clinical practice. The aim of this study was to assess the correlation between selected and delivered RF power for different generators. METHODS AND RESULTS: In an experimental setup, ablation catheters were connected to the EP Shuttle®, Ampere®, and SmartAblate® generators. The power delivered by the generators was measured using a current converter and an oscilloscope...
November 17, 2017: Journal of Cardiovascular Electrophysiology
https://www.readbyqxmd.com/read/29125413/a-computational-fluid-dynamics-simulation-framework-for-ventricular-catheter-design-optimization
#2
Sofy H Weisenberg, Stephanie C TerMaath, Charlotte N Barbier, Judith C Hill, James A Killeffer
OBJECTIVE Cerebrospinal fluid (CSF) shunts are the primary treatment for patients suffering from hydrocephalus. While proven effective in symptom relief, these shunt systems are plagued by high failure rates and often require repeated revision surgeries to replace malfunctioning components. One of the leading causes of CSF shunt failure is obstruction of the ventricular catheter by aggregations of cells, proteins, blood clots, or fronds of choroid plexus that occlude the catheter's small inlet holes or even the full internal catheter lumen...
November 10, 2017: Journal of Neurosurgery
https://www.readbyqxmd.com/read/29119636/gastric-accommodation-in-healthy-subjects-studied-by-ultrasound-manometry-and-impedancemetry
#3
E L Storlid, T Hausken, G A Lied, O H Gilja, J G Hatlebakk
BACKGROUND: Gastric accommodation to a meal may be important in the pathogenesis of upper gastrointestinal disorders, but has been difficult to investigate in a minimally invasive fashion. METHODS: We studied gastric and lower esophageal physiology during food intake, combining transabdominal ultrasound, multichannel high-resolution impedance-manometry (HRIM) and a symptom questionnaire. A HRIM catheter was distally positioned at incisura angularis and 300 mL saline with 75 g glucose was ingested...
November 9, 2017: Neurogastroenterology and Motility: the Official Journal of the European Gastrointestinal Motility Society
https://www.readbyqxmd.com/read/29119549/a-prototype-small-bore-ventilation-catheter-with-a-cuff-cuff-inflation-optimizes-ventilation-with-the-ventrain
#4
M W P de Wolf, T van der Beek, A E Hamaekers, M Theunissen, D Enk
BACKGROUND: Ventilation through small-diameter tubes typically precludes use of a cuff as this will impede the necessary passive outflow of gas alongside the tube's outer surface. Ventrain assists expiration and enables oxygenation and normoventilation through small-bore cannulas or catheters, particularly in obstructed airways. A small-bore ventilation catheter (SBVC; 40 cm long, 2.2 mm inner diameter) with a separate pressure monitoring lumen and a cuff was developed. Efficacy of oxygenation and ventilation with Ventrain through this catheter was investigated in sealed and open airways in a porcine cross-over study...
November 8, 2017: Acta Anaesthesiologica Scandinavica
https://www.readbyqxmd.com/read/29116663/higher-contact-force-energy-setting-and-impedance-rise-during-radiofrequency-ablation-predicts-charring-new-insights-from-contact-force-guided-in-vivo-ablation
#5
Hisaki Makimoto, Andreas Metzner, Roland Richard Tilz, Tina Lin, Christian-H Heeger, Andreas Rillig, Shibu Mathew, Christine Lemeš, Erik Wissner, Karl-Heinz Kuck, Feifan Ouyang
INTRODUCTION: Higher contact force (CF) theoretically increases the risk of blood charring, diminishing lesion formation. We aimed to investigate the relationship between CF, impedance change and char formation during pulmonary vein isolation (PVI). METHODS: CF was assessed during PVI in 65 patients. Radiofrequency ablation (RFA) with power-controlled mode was applied in the point-by-point manner. The RFA were divided into 5 groups: group-A [CF < 10 g], group-B (10 g≤CF < 20 g), group-C (20 g≤CF < 30 g), group-D (30 g≤CF < 40 g), and group-E (CF≥40 g)...
November 8, 2017: Journal of Cardiovascular Electrophysiology
https://www.readbyqxmd.com/read/29097486/practice-of-peritoneal-dialysis-catheter-flushing-in-australia-and-new-zealand-multi-center-cross-sectional-survey
#6
Yeoungjee Cho, Neil C Boudville, Suetonia Palmer, Josephine Chow, Carmel M Hawley, Matthew D Jose, Rob Macginley, Louis Huang, Jo-Anne Moodie, Thu Nguyen, Laura Robison, Jeffrey Wong, David W Johnson
BACKGROUND: Evidence of effective interventions to prevent peritoneal dialysis (PD) catheter malfunction before first use is presently insufficient to guide clinical care. Regular flushing of the PD catheter (e.g. before PD commencement) has been adopted by some practitioners in the belief that it will prevent catheter obstruction and/or malfunction. The aim of this study was to characterize and evaluate PD catheter flushing practices across Australian and New Zealand PD units. METHODS: An on-line survey was distributed to all 62 PD units in Australia (12 August 2016; n = 51) and New Zealand (2 February 2017; n = 11), with questions relating to PD catheter flushing practices, audit, and outcomes...
November 2, 2017: Peritoneal Dialysis International: Journal of the International Society for Peritoneal Dialysis
https://www.readbyqxmd.com/read/29089339/wave-intensity-analysis-provides-novel-insights-into-pulmonary-arterial-hypertension-and-chronic-thromboembolic-pulmonary-hypertension
#7
Junjing Su, Charlotte Manisty, Kim H Parker, Ulf Simonsen, Jens Erik Nielsen-Kudsk, Soren Mellemkjaer, Susan Connolly, P Boon Lim, Zachary I Whinnett, Iqbal S Malik, Geoffrey Watson, Justin E Davies, Simon Gibbs, Alun D Hughes, Luke Howard
BACKGROUND: In contrast to systemic hypertension, the significance of arterial waves in pulmonary hypertension (PH) is not well understood. We hypothesized that arterial wave energy and wave reflection are augmented in PH and that wave behavior differs between patients with pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH). METHODS AND RESULTS: Right heart catheterization was performed using a pressure and Doppler flow sensor-tipped catheter to obtain simultaneous pressure and flow velocity measurements in the pulmonary artery...
October 31, 2017: Journal of the American Heart Association
https://www.readbyqxmd.com/read/29063658/physiological-augmentation-of-esophageal-distension-pressure-and-peristalsis-during-conditions-of-increased-esophageal-emptying-resistance
#8
G J Brink, W Y Lei, T I Omari, M M J Singendonk, J S Hung, T T Liu, C H Yi, C L Chen
BACKGROUND: Abdominal compression has been implemented as a provocative maneuver in high-resolution impedance manometry (HRIM) to "challenge" normal esophageal physiology with the aim of revealing abnormal motor patterns which may explain symptoms. In this study, we measured the effects of abdominal compression on esophageal functioning utilizing novel pressure-impedance parameters and attempted to identify differences between healthy controls and globus patients. METHODS: Twenty-two healthy volunteers (aged 23-32 years, 41% female) and 22 globus patients (aged 23-72 years, 68% female) were evaluated with HRIM using a 3...
October 24, 2017: Neurogastroenterology and Motility: the Official Journal of the European Gastrointestinal Motility Society
https://www.readbyqxmd.com/read/29060676/gamma-variate-modeling-of-indicator-dilution-curves-in-electrical-impedance-tomography
#9
Benjamin Hentze, Thomas Muders, Henning Luepschen, Steffen Leonhardt, Christian Putensen, Marian Walter
Electrical impedance tomography (EIT) is a non-invasive imaging technique, that can be used to monitor regional lung ventilation (V̇) in intensive care units (ICU) at bedside. This work introduces a method to extract regional lung perfusion (Q̇) from EIT image streams in order to quantify regional gas exchange in the lungs. EIT data from a single porcine animal trial, recorded during injection of a contrast agent (NaCl 10%) into a central venous catheter (CVC), are used for evaluation. Using semi-negative matrix factorization (Semi-NMF) a set of source signals is extracted from the data...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29059883/monitoring-of-cardiac-output-and-lung-ventilation-by-electrical-impedance-tomography-in-a-porcine-model-of-acute-lung-injury
#10
Nadine Hochhausen, Henriette Dohmeier, Rolf Rossaint, Michael Czaplik
Adequate medical treatment of the Acute Respiratory Distress Syndrome is still challenging since patient-individual aspects have to be taken into account. Lung protective ventilation and hemodynamic stability have always been two of the most crucial aims of intensive care therapy. For both aspects, a continuous - preferably non-invasive - monitoring is desirable that is available at the bedside. Unfortunately, there is no technique clinically established yet, that provides both measurement of cardiac stroke volume and ventilation dynamics in real-time...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29059005/a-hand-held-robotic-device-for-peripheral-intravenous-catheterization
#11
Zhuoqi Cheng, Brian L Davies, Darwin G Caldwell, Giacinto Barresi, Qinqi Xu, Leonardo S Mattos
Intravenous catheterization is frequently required for numerous medical treatments. However, this process is characterized by a high failure rate, especially when performed on difficult patients such as newborns and infants. Very young patients have small veins, and that increases the chances of accidentally puncturing the catheterization needle directly through them. In this article, we present the design, development and experimental evaluation of a novel hand-held robotic device for improving the process of peripheral intravenous catheterization by facilitating the needle insertion procedure...
October 1, 2017: Proceedings of the Institution of Mechanical Engineers. Part H, Journal of Engineering in Medicine
https://www.readbyqxmd.com/read/28857171/characterization-of-swallow-modulation-in-response-to-bolus-volume-in-healthy-subjects-accounting-for-catheter-diameter
#12
Lara Ferris, Mistyka Schar, Lisa McCall, Sebastian Doeltgen, Ingrid Scholten, Nathalie Rommel, Charles Cock, Taher Omari
OBJECTIVES/HYPOTHESIS: Characterization of the pharyngeal swallow response to volume challenges is important for swallowing function assessment. The diameter of the pressure-impedance recording catheter may influence these results. In this study, we captured key physiological swallow measures in response to bolus volume utilizing recordings acquired by two catheters of different diameter. STUDY DESIGN: Ten healthy adults underwent repeat investigations with 8- and 10-Fr catheters...
August 31, 2017: Laryngoscope
https://www.readbyqxmd.com/read/28841588/thrombosis-in-adult-patients-with-acute-leukemia
#13
Maria Ilaria Del Principe, Domenico Del Principe, Adriano Venditti
PURPOSE OF REVIEW: Recent studies indicate that the risk of thrombosis in hematologic patients may be similar or even higher than that found in patients with solid tumors. However, available information about pathogenesis and incidence of thrombosis in acute leukemia is limited. This review focuses on mechanisms underlying thrombosis in acute leukemia and discusses recent literature data. RECENT FINDINGS: In the last few years, proofs have been provided that leukemic cells release free prothrombotic products, such as micro-vesicles, tissue factors, circulating free DNA and RNA...
November 2017: Current Opinion in Oncology
https://www.readbyqxmd.com/read/28833720/near-field-impedance-accurately-distinguishes-among-pericardial-intracavitary-and-anterior-mediastinal-position
#14
David A Burkland, Anand V Ganapathy, Mathews John, Brian D Greet, Mohammad Saeed, Abdi Rasekh, Mehdi Razavi
INTRODUCTION: Epicardial catheter ablation is increasingly used to treat arrhythmias with an epicardial component. Nevertheless, percutaneous epicardial access remains associated with a significant risk of major complications. Developing a technology capable of confirming proper placement within the pericardial space could decrease complication rates. The purpose of this study was to examine differences in bioimpedance among the pericardial space, anterior mediastinum, and right ventricle...
August 22, 2017: Journal of Cardiovascular Electrophysiology
https://www.readbyqxmd.com/read/28816432/an-integrated-microsystem-for-real-time-detection-and-threshold-activated-treatment-of-bacterial-biofilms
#15
Sowmya Subramanian, Ekaterina I Tolstaya, Thomas E Winkler, William E Bentley, Reza Ghodssi
Bacterial biofilms are the primary cause of infections in medical implants and catheters. Delayed detection of biofilm infections contributes to the widespread use of high doses of antibiotics, leading to the emergence of antibiotic-resistant bacterial strains. Accordingly, there is an urgent need for systems that can rapidly detect and treat biofilm infections in situ. As a step toward this goal, in this work we have developed for the first time a threshold-activated feedback-based impedance sensor-treatment system for combined real-time detection and treatment of biofilms...
September 20, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28805112/casting-doubt-on-the-value-of-assessing-the-cardiac-index-in-pregnancy
#16
Maya Ram, Anat Lavie, Shaul Lev, Yair Blecher, Uri Amikam, Yael Shulman, Tomer Avnon, Eran Weiner, Ariel Many
OBJECTIVES: The objective of this study is to assess the reliability of the cardiac index (CI) in healthy pregnant women at term by investigating the correlation between the cardiac output (CO) and the body surface area (BSA) using a novel non-invasive cardiography technique (NICaS™). METHODS: Sixty-one healthy, normotensive women with a singleton pregnancy at term (≥37 gestational weeks) participated in this prospective observational study between 1/2015 and 6/2015 L...
August 13, 2017: Journal of Maternal-fetal & Neonatal Medicine
https://www.readbyqxmd.com/read/28765087/circadian-variability-patterns-predict-and-guide-premature-ventricular-contraction-ablation-procedural-inducibility-and-outcomes
#17
David Hamon, Guillaume Abehsira, Kai Gu, Albert Liu, Marie Blaye-Felice Sadron, Sophie Billet, Thomas Kambur, Mohammed Amer Swid, Noel G Boyle, Gopi Dandamudi, Philippe Maury, Minglong Chen, John M Miller, Nicolas Lellouche, Kalyanam Shivkumar, Jason S Bradfield
BACKGROUND: Infrequent intraprocedural premature ventricular complexes (PVCs) may impede radiofrequency catheter ablation (RFA) outcome, and pharmacologic induction is unpredictable. OBJECTIVE: The purpose of this study was to determine whether PVC circadian variation could help predict drug response. METHODS: Consecutive patients referred for RFA with detailed Holter monitoring and frequent monomorphic PVCs were included. Patients were divided into 3 groups based on hourly PVC count relationship to corresponding mean heart rate (HR) during each of the 24 hours on Holter: fast-HR-dependent PVC (F-HR-PVC) type for a positive correlation (Pearson, P <...
July 29, 2017: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/28742775/estimation-of-stroke-volume-and-stroke-volume-changes-by-electrical-impedance-tomography
#18
Fernando José da Silva Ramos, André Hovnanian, Rogério Souza, Luciano C P Azevedo, Marcelo B P Amato, Eduardo L V Costa
BACKGROUND: Electrical impedance tomography (EIT) is a noninvasive imaging method that identifies changes in air and blood volume based on thoracic impedance changes. Recently, there has been growing interest in EIT to measure stroke volume (SV). The objectives of this study are as follows: (1) to evaluate the ability of systolic impedance variations (ΔZsys) to track changes in SV in relation to a baseline condition; (2) to assess the relationship of ΔZsys and SV in experimental subjects; and (3) to identify the influence of body dimensions on the relationship between ΔZsys and SV...
July 24, 2017: Anesthesia and Analgesia
https://www.readbyqxmd.com/read/28738493/-a-case-of-high-impedance-inducedby-radiofrequency-catheter-ablation-of-accessory-pathway
#19
Q Y Zhang, B Jiang, M Liu
No abstract text is available yet for this article.
July 24, 2017: Zhonghua Xin Xue Guan Bing za Zhi
https://www.readbyqxmd.com/read/28664343/catheter-ablation-of-atypical-atrial-flutter-a-novel-3d-anatomic-mapping-approach-to-quickly-localize-and-terminate-atypical-atrial-flutter
#20
Sri Sundaram, William Choe, J Ryan Jordan, Nate Mullins, Charles Boorman, Eric J Kessler, Sunil Nath
PURPOSE: This study aims to describe a novel method of High Density Activation Sequence Mapping combined with Voltage Gradient Mapping Overlay (HD-VGM) to quickly localize and terminate atypical atrial flutter. METHODS: Twenty-one patients presenting with 26 different atypical atrial flutter circuits after a previous catheter or surgical AF ablation were studied. HD-VGM was performed with a commercially available impedance-based mapping system to locate and successfully ablate the critical isthmus of each tachycardia circuit...
September 2017: Journal of Interventional Cardiac Electrophysiology: An International Journal of Arrhythmias and Pacing
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