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https://www.readbyqxmd.com/read/28227423/dynamic-mapping-of-ventricular-function-from-cardiovascular-magnetic-resonance-imaging
#1
Maria Panayiotou, Peter Mountney, Alexander Brost, Daniel Toth, Tom Jackson, Jonathan M Behar, Christopher A Rinaldi, R James Housden, Kawal S Rhode, Maria Panayiotou, Peter Mountney, Alexander Brost, Daniel Toth, Tom Jackson, Jonathan M Behar, Christopher A Rinaldi, R James Housden, Kawal S Rhode, Alexander Brost, Tom Jackson, Maria Panayiotou, Christopher A Rinaldi, Jonathan M Behar, R James Housden, Kawal S Rhode, Daniel Toth, Peter Mountney
Heart failure is associated with substantial mortality and morbidity and remains the most common diagnosis in older patients. Based on experimental electrophysiologic studies, cardiac resynchronization therapy (CRT) for heart failure results in a maximum resynchronization effect when applied to the most delayed left ventricular (LV) site. Current clinical practice is to identify the optimal site using separate visualisation of scar and activation information. These must be mentally mapped into 3D, which is challenging and time-consuming for the electrophysiologist...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227376/electrocardiogram-reconstruction-from-high-resolution-voltage-optical-mapping
#2
Ilija Uzelac, Conner Herndon, James Farmer, Flavio Fenton, Ilija Uzelac, Conner Herndon, James Farmer, Flavio Fenton, Ilija Uzelac, Conner Herndon, James Farmer, Flavio Fenton
Electrocardiogram recordings during opucal mapping experiments in heart tissue are commonly used tu monitor the health of the preparation and to obtain dominant frequencies during arrhythmic and defibrillatory studies. However the use of ECG reconstructed from optical mapping is seldom used and to date it has not been strictly validated. In this manuscript we present the first detailed validation and comparison of Optical Mapping ECG, or OM-ECG, with standard ECG recordings by calculating the electrostatic potential in space as a function of the voltage measured optically and describe the different approximations that can be used to obtain unipolar or bipolar ECG recordings...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226460/pro-arrhythmic-effect-of-heart-rate-variability-during-periodic-pacing
#3
Kanchan Kulkarni, Steven W Lee, Elena G Tolkacheva, Kanchan Kulkarni, Steven W Lee, Elena G Tolkacheva, Elena G Tolkacheva, Steven W Lee, Kanchan Kulkarni
Clinically, healthy hearts have been associated with a high ventricular heart rate variability (HRV) while diseased hearts have been known to exhibit low ventricular HRV. Hence, low HRV is suggested to be a marker of cardiac ventricular arrhythmias. Over the past few years, there has been considerable amount of interest in incorporating HRV in pacing to emulate healthy heart conditions and re-stabilize the electrical activity in diseased hearts. Recently, we used single cell numerical simulations to demonstrate that HRV incorporated into periodic pacing promotes alternans formation and thus, can be pro-arrhythmic...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226451/non-invasive-imaging-of-ventricular-activation-during-pacing-and-arrhythmia-methods-and-validation
#4
Long Yu, Steven Pogwizd, Bin He, Long Yu, Steven Pogwizd, Bin He, Bin He, Steven Pogwizd, Long Yu
Cardiovascular disease continued to be a leading killer world widely. Each year, about 400,000 cases of sudden cardiac arrest are reported in the U.S. alone. Clinically, radio-frequency ablative procedure has become widely applied in the treatment of ventricular arrhythmia. Non-invasive approaches have been demonstrated to be able to provide important information on the arrhythmogenesis and potentially assist in the clinical practice. In this work, we develop and validate a novel temporal sparse based imaging method, Cardiac Electrical Sparse Imaging (CESI)...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28213506/role-of-apamin-sensitive-calcium-activated-small-conductance-potassium-currents-on-the-mechanisms-of-ventricular-fibrillation-in-pacing-induced-failing-rabbit-hearts
#5
Dechun Yin, Yu-Cheng Hsieh, Wei-Chung Tsai, Adonis Zhi-Yang Wu, Zhaolei Jiang, Yi-Hsin Chan, Dongzhu Xu, Na Yang, Changyu Shen, Zhenhui Chen, Shien-Fong Lin, Peng-Sheng Chen, Thomas H Everett
BACKGROUND: Ventricular fibrillation (VF) during heart failure is characterized by stable reentrant spiral waves (rotors). Apamin-sensitive small-conductance calcium-activated potassium currents (IKAS) are heterogeneously upregulated in failing hearts. We hypothesized that IKAS influences the location and stability of rotors during VF. METHODS AND RESULTS: Optical mapping was performed on 9 rabbit hearts with pacing-induced heart failure. The epicardial right ventricular and left ventricular surfaces were simultaneously mapped in a Langendorff preparation...
February 2017: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/28213055/electrophysiological-measurements-that-can-explain-and-guide-temporary-accelerated-pacing-to-avert-re-occurrence-of-torsade-de-pointes-arrhythmias-in-the-canine-chronic-atrioventricular-block-model
#6
Sofieke C Wijers, Alexandre Bossu, Albert Dunnink, Jet D M Beekman, Rosanne Varkevisser, Alfonso Aranda Hernández, Mathias Meine, Marc A Vos
BACKGROUND: Pacing at higher rates is known to suppress Torsade de Pointes (TdP) arrhythmias. Nevertheless, exact application and mechanism need further clarification. In the anesthetized, canine, chronic atrioventricular block model, ventricular remodeling is responsible for a high and reproducible incidence of TdP upon a challenge with dofetilide. OBJECTIVE: We used this model to investigate by what mechanism accelerated pacing averts TdP and what repolarization parameter could be used to guide temporary applied accelerated pacing (TAP)...
February 14, 2017: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/28212738/delayed-efficacy-of-radiofrequency-catheter-ablation-on-ventricular-arrhythmias-originating-from-the-left-ventricular-anterobasal-wall
#7
Ligang Ding, Bingbo Hou, Lingmin Wu, Yu Qiao, Wei Sun, Jinrui Guo, Lihui Zheng, Gang Chen, Linfeng Zhang, Shu Zhang, Yan Yao
BACKGROUND: Ventricular arrhythmias (VAs) originating from the left ventricular anterobasal wall (LV-ABW) may represent a therapeutic challenge. OBJECTIVE: The purpose of this study was to investigate the delayed efficacy of radiofrequency catheter (RFCA) ablation without an epicardial approach on VAs originating from the LV-ABW. METHODS: Eighty patients (mean age 46.9 ± 14.9 years; 47 male) with VAs originating from the LV-ABW were enrolled...
March 2017: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/28190374/the-use-of-quality-adjusted-life-years-in-cost-effectiveness-analyses-in-palliative-care-mapping-the-debate-through-an-integrative-review
#8
Anne B Wichmann, Eddy Mm Adang, Peep Fm Stalmeier, Sinta Kristanti, Lieve Van den Block, Myrra Jfj Vernooij-Dassen, Yvonne Engels
BACKGROUND: In cost-effectiveness analyses in healthcare, Quality-Adjusted Life Years are often used as outcome measure of effectiveness. However, there is an ongoing debate concerning the appropriateness of its use for decision-making in palliative care. AIM: To systematically map pros and cons of using the Quality-Adjusted Life Year to inform decisions on resource allocation among palliative care interventions, as brought forward in the debate, and to discuss the Quality-Adjusted Life Year's value for palliative care...
February 1, 2017: Palliative Medicine
https://www.readbyqxmd.com/read/28186067/national-monitoring-and-evaluation-of-health-it-protocol-for-a-scoping-review
#9
Sidsel Villumsen, Christian Nøhr
BACKGROUND: Monitoring the pace of Health Information Technology (HIT) adoption across states is critical for providing data to formulate future national and regional HIT policies. However, repeated monitoring of the progress on implementation of the strategies is often scarce. The lack of systematic monitoring of progress in availability and use of HIT has led to a need for an overview of the key concepts and methodologies used in the scattered scientific literature. The scoping study aims at achieving both in-depth and broad results, identifying all relevant material, regardless of the design...
2017: Studies in Health Technology and Informatics
https://www.readbyqxmd.com/read/28177123/katp-channel-inhibition-blunts-electromechanical-decline-during-hypoxia-in-left-ventricular-working-rabbit-hearts
#10
Kara Garrott, Sarah Kuzmiak-Glancy, Anastasia Wengrowski, Hanyu Zhang, Jack Rogers, Matthew Kay
Sarcolemmal KATP channel activation in isolated cells is generally understood, yet the relationship between myocardial oxygenation and KATP activation in excised working rabbit hearts remains unknown. We optically mapped action potentials (APs) in excised rabbit hearts to test the hypothesis that hypoxic changes would be more severe in LV working hearts (LWHs) than Langendorff (LANG) perfused hearts. We further hypothesized that KATP inhibition would prevent those changes. Optical APs were mapped while measuring LV developed pressure (LVDP), coronary flow rate (CFR), and oxygen consumption (MVO2 ) in LANG and LWHs...
February 8, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28167087/pace-mapping-to-localize-the-critical-isthmus-of-ventricular-tachycardia
#11
REVIEW
Christian de Chillou, Jean-Marc Sellal, Isabelle Magnin-Poull
Most postinfarct ventricular tachycardias (VT) are sustained by a reentrant mechanism. The "protected isthmus" of the reentrant circuit is critical for the maintenance of VTs and the target for catheter ablation. In this article, the authors describe the technique of pace-mapping during sinus rhythm to unmask postinfarct VT isthmuses. A pace-mapping map should be considered as the surrogate of an activation map during VT, in both patients with a normal heart and patients with a structural heart disease. Pace mapping is useful to unmask VT isthmuses in patients with postinfarct reentrant VTs...
March 2017: Cardiac Electrophysiology Clinics
https://www.readbyqxmd.com/read/28167086/entrainment-mapping
#12
REVIEW
Saurabh Kumar, Usha B Tedrow, William G Stevenson
Mapping during ventricular tachycardia (VT) aims to elucidate mechanism, describe myocardial propagation, and identify the origin and critical regions of VT that can be targeted for ablation, most commonly with radiofrequency ablation. Most VTs in structural heart disease are due to macro-reentry in and around scar. A combination of mapping techniques, including mapping to identify the arrhythmia substrate, activation sequence mapping, pace-mapping, and entrainment mapping, may be used to identify putative ablation targets...
March 2017: Cardiac Electrophysiology Clinics
https://www.readbyqxmd.com/read/28163058/limb-position-drift-results-from-misalignment-of-proprioceptive-and-visual-maps
#13
Jacqueline R Patterson, Liana E Brown, David A Wagstaff, Robert L Sainburg
Previous work (Brown et al., 2003a,b) has shown that limb position drifts when individuals make repetitive movements in the absence of visual feedback. The purpose of this study was to examine whether limb position drift might reflect a misalignment in visual and proprioceptive maps by examining the nature of information used to specify new movements from a drifted limb position. In a virtual reality (VR) environment, participants made continuous movements with their dominant right hand between two targets positioned 15cm apart, paced by a 0...
February 3, 2017: Neuroscience
https://www.readbyqxmd.com/read/28140304/electrical-approach-to-improve-left-ventricular-activation-during-right-ventricle-stimulation
#14
María Paula Bonomini, Daniel F Ortega, Luis D Barja, Nicolasa Mangani, Analía Paolucci, Emilio Logarzo
Coronary sinus mapping is commonly used to evaluate left atrial activation. Herein, we propose to use it to assess which right ventricular pacing modality produces the shortest left ventricular activation times (R-LVtime) and the narrowest QRS widths. Three study groups were defined: 54 controls without intraventricular conduction disturbances; 15 patients with left bundle branch block, and other 15 with right bundle branch block. Left ventricular activation times and QRS widths were evaluated among groups under sinus rhythm, right ventricular apex, right ventricular outflow tract and high output septal zone (SEPHO)...
2017: Medicina
https://www.readbyqxmd.com/read/28120950/fencing-bodes-a-rapid-collapse-of-the-unique-greater-mara-ecosystem
#15
Mette Løvschal, Peder Klith Bøcher, Jeppe Pilgaard, Irene Amoke, Alice Odingo, Aggrey Thuo, Jens-Christian Svenning
With land privatization and fencing of thousands of hectares of communal grazing areas, East Africa is struggling with one of the most radical cultural and environmental changes in its history. The 668,500-hectare Greater Mara is of crucial importance for the great migrations of large mammals and for Maasai pastoralist culture. However, the magnitude and pace of these fencing processes in this area are almost completely unknown. We provide new evidence that fencing is appropriating land in this area at an unprecedented and accelerating speed and scale...
January 25, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28113292/non-invasive-personalisation-of-a-cardiac-electrophysiology-model-from-body-surface-potential-mapping
#16
Sophie Giffard-Roisin, Thomas Jackson, Lauren Fovargue, Jack Lee, Herve Delingette, Reza Razavi, Nicholas Ayache, Maxime Sermesant
Modelling cardiac electrophysiology (EP) can help understand pathologies and predict the response to therapies. Moreover, estimating patient-specific parameters of the EP model is crucial to obtain personalised information. The novelty of this paper is to use non-invasive data (body surface potential mapping, BSPM) in order to personalise the main parameters of a cardiac EP model for predicting different pacing conditions. First, an efficient forward model is proposed, coupling the Mitchell- Schaeffer transmembrane potential model with a current dipole formulation...
November 16, 2016: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28108548/the-effect-of-left-ventricular-pacing-on-transmural-activation-delay-in-myopathic-human-hearts
#17
Andreu Porta-Sánchez, Paul Angaran, Stéphane Massé, Krishnakumar Nair, Talha Farid, Karthikeyan Umapathy, John Asta, Sigfus Gizurarson, Kumaraswamy Nanthakumar
AIMS: Left ventricular (LV) epicardial pacing (LVEpiP) in human myopathic hearts does not decrease global epicardial activation delay compared with right ventricular (RV) endocardial pacing (RVEndoP); however, the effect on transmural activation delay has not been evaluated. To characterize the transmural electrical activation delay in human myopathic hearts during RVEndoP and LVEpiP compared with global epicardial activation delay. METHODS AND RESULTS: Explanted hearts from seven patients (5 male, 46 ± 10 years) undergoing cardiac transplantation were Langendorff-perfused and mapped using an epicardial sock electrode array (112 electrodes) and 25 transmural plunge needles (four electrodes, 2 mm spacing), for a total of 100 unipolar transmural electrodes...
January 20, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/28102001/evaluation-of-the-hybrid-resolution-pace-model-for-the-study-of-folding-insertion-and-pore-formation-of-membrane-associated-peptides
#18
Michael D Ward, Shivangi Nangia, Eric R May
The PACE force field presents an attractive model for conducting molecular dynamics simulations of membrane-protein systems. PACE is a hybrid model, in which lipids and solvents are coarse-grained consistent with the MARTINI mapping, while proteins are described by a united atom model. However, given PACE is linked to MARTINI, which is widely used to study membranes, the behavior of proteins interacting with membranes has only been limitedly examined in PACE. In this study, PACE is used to examine the behavior of several peptides in membrane environments, namely WALP peptides, melittin and influenza hemagglutinin fusion peptide (HAfp)...
January 19, 2017: Journal of Computational Chemistry
https://www.readbyqxmd.com/read/28098354/concealed-accessory-pathways-with-a-single-ventricular-and-two-discrete-atrial-insertion-sites
#19
Ryan T Kipp, Raed Abu Sham'a, Ito Hiroyuki, Frederick T Han, Marwan Refaat, Jonathan C Hsu, Michael E Field, Douglas E Kopp, Gregory M Marcus, Melvin M Scheinman, Kurt S Hoffmayer
BACKGROUND: Atrioventricular reciprocating tachycardia utilizing a concealed accessory pathway is common. It is well appreciated that some patients may have multiple accessory pathways with separate atrial and ventricular insertion sites. METHODS: We present three cases of AVRT utilizing concealed pathways with evidence that each utilizing a single ventricular insertion and two discrete atrial insertion sites. RESULTS: In case one, two discrete atrial insertion sites were mapped in two separate procedures, and only during the second ablation was the Kent potential identified...
January 18, 2017: Pacing and Clinical Electrophysiology: PACE
https://www.readbyqxmd.com/read/28096741/a-day-in-the-life-of-third-year-medical-students-using-an-ethnographic-method-to-understand-information-seeking-and-use
#20
Andrea B Twiss-Brooks, Ricardo Andrade, Michelle B Bass, Barbara Kern, Jonna Peterson, Debra A Werner
OBJECTIVE: The authors undertook this project to learn how third-year medical students seek and use information in the course of daily activities, especially activities conducted in clinical settings in a variety of institutions. METHODS: We recruited sixty-eight third-year undergraduate medical school students to create a mapping diary of a day that included clinical activities. We conducted semi-structured interviews based on the mapping diaries. Using content and thematic analyses of the resulting interview transcripts, we developed an ethnographic case study for each participant...
January 2017: Journal of the Medical Library Association: JMLA
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