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https://www.readbyqxmd.com/read/27921187/rotor-tracking-using-phase-of-electrograms-recorded-during-atrial-fibrillation
#1
Caroline H Roney, Chris D Cantwell, Norman A Qureshi, Rasheda A Chowdhury, Emmanuel Dupont, Phang Boon Lim, Edward J Vigmond, Jennifer H Tweedy, Fu Siong Ng, Nicholas S Peters
Extracellular electrograms recorded during atrial fibrillation (AF) are challenging to interpret due to the inherent beat-to-beat variability in amplitude and duration. Phase mapping represents these voltage signals in terms of relative position within the cycle, and has been widely applied to action potential and unipolar electrogram data of myocardial fibrillation. To date, however, it has not been applied to bipolar recordings, which are commonly acquired clinically. The purpose of this study is to present a novel algorithm for calculating phase from both unipolar and bipolar electrograms recorded during AF...
December 5, 2016: Annals of Biomedical Engineering
https://www.readbyqxmd.com/read/27920835/atriofascicular-pathway-detection-with-novel-ablation-catheter
#2
Padmanabhan Shakkottai, Adrian Baranchuk, Neil Hobson, Jane Caldwell
Atriofascicular pathways are a rare cause of antidromic atrioventricular reciprocating tachycardia. The IntellaTip MiFi ablation catheter (Boston Scientific, MA, USA) is a novel ablation catheter that allows enhanced signal clarity with highly localized electrograms. This is the first report of this catheter being successfully used to map and ablate the atriofascicular pathway potentials.
December 2016: Journal of Arrhythmia
https://www.readbyqxmd.com/read/27920828/detection-of-sequential-activation-of-left-atrium-and-coronary-sinus-musculature-in-the-general-population
#3
Masaki Ota, Yoshiaki Kaneko, Tadashi Nakajima, Tadanobu Irie, Takafumi Iijima, Akihiro Saito, Masahiko Kurabayashi
BACKGROUND: The direction of impulse propagation across the coronary sinus (CS) musculature (CSM) is an important piece of the mechanistic puzzle underlying atrial tachyarrhythmias. We hypothesized that in the general population, the sequence of left atrial (LA) to CSM electrograms recorded in the CS reflects the direction of impulse propagation over the CSM. METHODS: We studied 19 patients with atrioventricular (AV) reentrant tachycardia (RT) utilizing a left-sided accessory pathway (AP) and 21 patients with typical counterclockwise atrial flutter (AFL)...
December 2016: Journal of Arrhythmia
https://www.readbyqxmd.com/read/27913399/development-of-time-and-voltage-domain-mapping-v-t-mapping-to-localize-ventricular-tachycardia-channels-during-sinus-rhythm
#4
Sachin Nayyar, Pawel Kuklik, Anand N Ganesan, Thomas R Sullivan, Lauren Wilson, Glenn D Young, Prashanthan Sanders, Kurt C Roberts-Thomson
BACKGROUND: In ventricular scar, impulse spread is slow because it traverses split and zigzag channels of surviving muscle. We aimed to evaluate scar electrograms to determine their local delay (activation time) and inequality in voltage splitting (entropy), and their relationship to channels. We reasoned that unlike innocuous channels, which are often short with multiple side branches, ventricular tachycardia (VT) supporting channels have very slow impulse spread and possess low entropy because of their longer protected length and relative lack of side-branching...
December 2016: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/27909501/-two-for-the-price-of-one-a-single-lead-implantable-cardioverter-defibrillator-system-with-a-floating-atrial-dipole
#5
REVIEW
Nicole E Worden Md, Musab Alqasrawi Md, Siva M Krothapalli Md, Alexander Mazur Md
In patients known to be a high risk for sudden cardiac arrest, implantable cardioverter defibrillators (ICD) are a proven therapy to reduce risk of death. However, in patients without conventional indications for pacing, the optimal strategy for type of device, dual- versus single-chamber, remains debatable. The benefit of prophylactic pacing in this category of patients has never been documented. Although available atrial electrograms in a dual chamber system improve interpretation of stored arrhythmia events, allow monitoring of atrial fibrillation and may potentially reduce the risk of inappropriate shocks by enhancing automated arrhythmia discrimination, the use of dual-chamber ICDs has a number of disadvantages...
April 2016: Journal of Atrial Fibrillation
https://www.readbyqxmd.com/read/27908173/pacemaker-and-icd-oversensing-induced-by-movements-near-the-mri-scanner-bore
#6
E Mattei, F Censi, G Calcagnini, R Falsaperla, E Genovese, A Napolitano, V Cannatà
PURPOSE: The effect of the movement near the MRI scanner bore for people with a pacemaker (PM) or an implantable cardioverter defibrillator (ICD) is experimentally evaluated and discussed. METHODS: The authors performed in vitro measurements on a saline-filled human-shaped phantom (male, 170 cm height), equipped first with an MR-conditional PM (bicameral configuration, DDD programming), then with an MR-conditional ICD (biventricular configuration, detection algorithms enable but shock delivery disable)...
December 2016: Medical Physics
https://www.readbyqxmd.com/read/27906707/hybrid-ablation-for-atrial-fibrillation-current-approaches-and-future-directions
#7
Gianluigi Bisleri, Benedict Glover
PURPOSE OF REVIEW: Catheter ablation of atrial fibrillation has rapidly evolved during the past decade: although the treatment of paroxysmal atrial fibrillation via a transcatheter approach has been consistently successful, persistent and long-standing atrial fibrillation still represents a major clinical challenge with less favorable outcomes to date. Because novel, minimally invasive surgical approaches have been developed for atrial fibrillation ablation, the aim of the present review is to analyze the current evidence surrounding the integration of surgical and transcatheter strategies in a hybrid fashion for the treatment of atrial fibrillation...
January 2017: Current Opinion in Cardiology
https://www.readbyqxmd.com/read/27906655/methodology-considerations-in-phase-mapping-of-human-cardiac-arrhythmias
#8
Ramya Vijayakumar, Sunil K Vasireddi, Phillip S Cuculich, Mitchell N Faddis, Yoram Rudy
BACKGROUND: Phase analysis of cardiac arrhythmias, particularly atrial fibrillation, has gained interest because of the ability to detect organized stable drivers (rotors) and target them for therapy. However, the lack of methodology details in publications on the topic has resulted in ongoing debate over the phase mapping technique. By comparing phase maps and activation maps, we examined advantages and limitations of phase mapping. METHODS AND RESULTS: Seven subjects were enrolled...
November 2016: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/27906653/longer-left-ventricular-electric-delay-reduces-mitral-regurgitation-after-cardiac-resynchronization-therapy-mechanistic-insights-from-the-smart-av-study-smartdelay-determined-av-optimization-a-comparison-to-other-av-delay-methods-used-in-cardiac-resynchronization
#9
Neal A Chatterjee, Michael R Gold, Alan D Waggoner, Michael H Picard, Kenneth M Stein, Yinghong Yu, Timothy E Meyer, Nicholas Wold, Kenneth A Ellenbogen, Jagmeet P Singh
BACKGROUND: Mitral regurgitation (MR) is associated with worse survival in those undergoing cardiac resynchronization therapy (CRT). Left ventricular (LV) lead position in CRT may ameliorate mechanisms of MR. We examine the association between a longer LV electric delay (QLV) at the LV stimulation site and MR reduction after CRT. METHODS AND RESULTS: QLV was assessed retrospectively in 426 patients enrolled in the SMART-AV study (SmartDelay Determined AV Optimization: A Comparison to Other AV Delay Methods Used in CRT)...
November 2016: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/27892602/the-analog-blanking-period-of-implantable-cardiac-rhythm-devices
#10
S Serge Barold, Andreas Kucher
BACKGROUND: Analog blanking periods (BP) that hold down the display of electrograms (EGM) in cardiac rhythm devices have received much less attention than the well-known digital blanking periods which do not influence the EGM display. In Biotronik devices, when a paced event initiates an analog BP in one chamber [right atrium (RA), right ventricle (RV) or left ventricle (LV)], an identical cross-chamber analog BP starts in the other 2 chambers. METHODOLOGY: All clinical observations were recorded from patients with Biotronik devices...
November 28, 2016: Pacing and Clinical Electrophysiology: PACE
https://www.readbyqxmd.com/read/27884253/the-quest-for-new-approaches-in%C3%A2-myocarditis-and-inflammatory%C3%A2-cardiomyopathy
#11
REVIEW
Stephane Heymans, Urs Eriksson, Jukka Lehtonen, Leslie T Cooper
Myocarditis is a diverse group of heart-specific immune processes classified by clinical and histopathological manifestations. Up to 40% of dilated cardiomyopathy is associated with inflammation or viral infection. Recent experimental studies revealed complex regulatory roles for several microribonucleic acids and T-cell and macrophage subtypes. Although the prevalence of myocarditis remained stable between 1990 and 2013 at about 22 per 100,000 people, overall mortality from cardiomyopathy and myocarditis has decreased since 2005...
November 29, 2016: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/27878578/the-double-guidewire-approach-for-transcoronary-pacing-in-a%C3%A2-porcine-model
#12
K M Heinroth, S Unverzagt, D Mahnkopf, S Frantz, R Prondzinsky
BACKGROUND: Transcoronary pacing is used for treatment of unheralded bradycardias in the setting of percutaneous coronary interventions (PCI). OBJECTIVES: In the present study we introduced a new concept - the double guidewire approach - for transcoronary pacing in a porcine model. METHODS: Transcoronary pacing was applied in 16 adult pigs under general anaesthesia in an animal catheterization laboratory. A special guidewire with electrical insulation by PTFE coating except for the distal part of the guidewire was positioned in the periphery of a coronary artery serving as the cathode...
November 23, 2016: Medizinische Klinik, Intensivmedizin und Notfallmedizin
https://www.readbyqxmd.com/read/27875591/reentry-and-ectopic-pacemakers-emerge-in-a-three-dimensional-model-for-a-slab-of-cardiac-tissue-with-diffuse-microfibrosis-near-the-percolation-threshold
#13
Sergio Alonso, Rodrigo Weber Dos Santos, Markus Bär
Arrhythmias in cardiac tissue are generally associated with irregular electrical wave propagation in the heart. Cardiac tissue is formed by a discrete cell network, which is often heterogeneous. Recently, it was shown in simulations of two-dimensional (2D) discrete models of cardiac tissue that a wave crossing a fibrotic, heterogeneous region may produce reentry and transient or persistent ectopic activity provided the fraction of conducting connections is just above the percolation threshold. Here, we investigate the occurrence of these phenomena in three-dimensions by simulations of a discrete model representing a thin slab of cardiac tissue...
2016: PloS One
https://www.readbyqxmd.com/read/27875133/bipolar-intracardiac-electrogram-active-interval-extraction-during-atrial-fibrillation
#14
Mohammad Hassan Shariat, Saeed Gazor, Damian Redfearn
OBJECTIVE: We introduce novel methods to identify the active intervals (AIs) of intracardiac electrograms (IEGMs) during complex arrhythmias, such as atrial fibrillation (AF). METHODS: We formulate the AI extraction problem, which consists of estimating the beginning and duration of the AIs, as a sequence of hypothesis tests. In each test, we compare the variance of a small portion of the bipolar IEGM with its adjacent segments. We propose modified general-likelihood-ratio (MGLR) and separating-function-estimation tests; we derive five test statistics (TSs), and show that the AIs can be obtained by threshold crossing the TSs...
November 18, 2016: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/27873155/physiology-based-regularization-of-the-electrocardiographic-inverse-problem
#15
Matthijs J M Cluitmans, Michael Clerx, Nele Vandersickel, Ralf L M Peeters, Paul G A Volders, Ronald L Westra
The inverse problem of electrocardiography aims at noninvasively reconstructing electrical activity of the heart from recorded body-surface electrocardiograms. A crucial step is regularization, which deals with ill-posedness of the problem by imposing constraints on the possible solutions. We developed a regularization method that includes electrophysiological input. Body-surface potentials are recorded and a computed tomography scan is performed to obtain the torso-heart geometry. Propagating waveforms originating from several positions at the heart are simulated and used to generate a set of basis vectors representing spatial distributions of potentials on the heart surface...
November 21, 2016: Medical & Biological Engineering & Computing
https://www.readbyqxmd.com/read/27870970/panoramic-characterization-of-endocardial-left-atrial-activation-during-human-persistent-af-insights-from-non-contact-mapping
#16
Geoffrey Lee, Alex J A McLellan, Ross J Hunter, Matthew J Lovell, Malcolm Finlay, Waqas Ullah, Mehul B Dhinoja, Simon Sporton, Mark J Earley, Richard J Schilling
BACKGROUND: The relative importance of focal drivers, multiple wavelets, rotors and endocardial-epicardial circuits in the maintenance of persistent AF remains unclear. Our objective was to characterize AF wavefront (WF) dynamics during persistent AF. METHODS: The Ensite 3000 (St Jude Medical) non-contact mapping system was used to map the LA of 15 patients with persistent AF. Wavefronts were classified into planar WFs, rotors or focal WFs. For each new WF the site of origin, the unipolar electrogram, and propagation patterns were determined...
November 9, 2016: International Journal of Cardiology
https://www.readbyqxmd.com/read/27867071/evaluation-of-a-novel-high-resolution-mapping-system-for-catheter-ablation-of-ventricular-arrhythmias
#17
Karthik Viswanathan, Lilian Mantziari, Charles Butcher, Emily Hodkinson, Eric Lim, Habib Khan, Sandeep Panikker, Shouvik Haldar, Julian W E Jarman, David G Jones, Wajid Hussain, John P Foran, Vias Markides, Tom Wong
BACKGROUND: The mapping of ventricular arrhythmias in humans using a mini-basket 64-electrode catheter paired with a novel automatIc mapping system (Rhythmia(TM)) has not been evaluated. OBJECTIVE: To evaluate the safety and efficacy of mapping ventricular arrhythmias and clinical outcomes after ablation using this system. METHODS: Electroanatomic (EA) maps for ventricular arrhythmias were obtained during 20 consecutive procedures in 19 patients (ventricular tachycardia [VT] 12; ventricular ectopy [VE] 7)...
November 17, 2016: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/27853943/endocardial-voltage-mapping-of-pulmonary-veins-with-an-ultra-high-resolution-system-to-evaluate-atrial-myocardial-extensions
#18
Francesco Santoro, Christian Sohns, Ardan M Saguner, Natale Daniele Brunetti, Christine Lemes, Shibu Mathew, Christian-H Heeger, Bruno Reißmann, Tilman Maurer, Johannes Riedl, Thomas Fink, Kentaro Hayashi, Feifan Ouyang, Matteo Di Biase, Karl-Heinz Kuck, Andreas Metzner
INTRODUCTION: Atrial fibrillation (AF) is mainly triggered by arrhythmogenic foci originating from atrial myocardial extensions (MEs) into the pulmonary veins (PVs). Aim of the study was to evaluate endocardial voltage maps of PVs as a surrogate parameter for the extent of MEs in subjects with AF through a ultra-high-density mapping system. METHODS: Sixty-four bipolar electrograms were recorded simultaneously from the Orion mini-basket catheter placed in 72 PVs of 18 consecutive patients with paroxysmal/persistent AF undergoing PV isolation (PVI)...
November 16, 2016: Clinical Research in Cardiology: Official Journal of the German Cardiac Society
https://www.readbyqxmd.com/read/27847262/the-angelmed-guardian-system-is-there-a-role-for-implantable-devices-to-detect-coronary-artery-occlusion
#19
Toby Rogers, Arie Steinvil, Rebecca Torguson, Ron Waksman
The AngelMed Guardian System is an implantable device similar to a single chamber pacemaker that continuously monitors the intracardiac electrogram for evidence of ST segment shift indicating acute coronary artery occlusion. The system aims to reduce time to presentation by alerting patients to present to a medical facility whether symptoms are present or not. In March 2016, the US Food and Drug Administration (FDA) assembled a meeting of the Circulatory System Devices Panel to review the results of the AngelMed for Early Recognition and Treatment of STEMI (ALERTS) pivotal trial and the accompanying premarket approval (PMA) application for regulatory approval of the AngelMed Guardian System in the US...
October 8, 2016: Cardiovascular Revascularization Medicine: Including Molecular Interventions
https://www.readbyqxmd.com/read/27826128/durability-of-wide-area-left-atrial-appendage-isolation-results-from-extensive-catheter-ablation-for-the-treatment-of-persistent-atrial-fibrillation
#20
Bruno Reissmann, Andreas Rillig, Erik Wissner, Roland Tilz, Michael Schlüter, Christian Sohns, Christian Heeger, Shibu Mathew, Tilman Maurer, Christine Lemes, Thomas Fink, Peter Wohlmuth, Francesco Santoro, Johannes Riedl, Feifan Ouyang, Karl-Heinz Kuck, Andreas Metzner
BACKGROUND: Extensive ablation strategies are currently performed in addition to pulmonary vein isolation (PVI) to improve the clinical outcome of patients with drug-refractory persistent atrial fibrillation (AF). Ablation of complex fractionated atrial electrograms (CFAE), linear lesions and/or isolation of the left atrial appendage (LAA) are thought to improve arrhythmia-free survival. OBJECTIVE: This study sought to assess the durability of wide-area LAA isolation (LAAI) achieved by PVI, an anterior line and a mitral isthmus line...
November 5, 2016: Heart Rhythm: the Official Journal of the Heart Rhythm Society
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