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https://www.readbyqxmd.com/read/29769223/comprehensive-multicenter-study-of-the-common-isthmus-in-post-atrial-fibrillation-ablation-multiple-loop-atrial-tachycardia
#1
Masateru Takigawa, Nicolas Derval, Philippe Maury, Ruairidh Martin, Arnaud Denis, Shinsuke Miyazaki, Seigo Yamashita, Antonio Frontera, Konstantinos Vlachos, Takeshi Kitamura, Ghassen Cheniti, Greégoire Massoullieé, Nathaniel Thompson, Claire A Martin, Michael Wolf, Xavier Pillois, Josselin Duchateau, Nicolas Klotz, Alexandre Duparc, Anne Rollin, Thomas Pambrun, Frédéric Sacher, Hubert Cochet, Mélèze Hocini, Michel Haiïssaguerre, Pierre Jaiïs
BACKGROUND: Characteristics of multiple-loop atrial tachycardia (AT) circuits have never precisely examined. METHODS: In 193 consecutive post-atrial fibrillation ablation patients with AT, 44 multiple-loop ATs including 42 dual-loop AT and 2 triple-loop AT in 41 (21.2%) were diagnosed with the high-resolution mapping system and analyzed off-line. RESULTS: In dual-loop ATs, 3 types were identified: type M, a combination of 2 anatomic macroreentrant ATs (AMATs) in 19 (43...
June 2018: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/29765687/machine-learning-methods-for-locating-re-entrant-drivers-from-electrograms-in-a-model-of-atrial-fibrillation
#2
Max Falkenberg McGillivray, William Cheng, Nicholas S Peters, Kim Christensen
Mapping resolution has recently been identified as a key limitation in successfully locating the drivers of atrial fibrillation (AF). Using a simple cellular automata model of AF, we demonstrate a method by which re-entrant drivers can be located quickly and accurately using a collection of indirect electrogram measurements. The method proposed employs simple, out-of-the-box machine learning algorithms to correlate characteristic electrogram gradients with the displacement of an electrogram recording from a re-entrant driver...
April 2018: Royal Society Open Science
https://www.readbyqxmd.com/read/29759839/short-lasting-episodes-of-torsade-de-pointes-in-the-chronic-atrioventricular-block-dog-model-have-a-focal-mechanism-while-longer-lasting-episodes-are-maintained-by-re-entry
#3
Nele Vandersickel, Alexandre Bossu, Jan De Neve, Albert Dunnink, Veronique M F Meijborg, Marcel A G van der Heyden, Jet D M Beekman, Jacques M T De Bakker, Marc A Vos, Alexander V Panfilov
OBJECTIVES: This study investigated the arrhythmogenic mechanisms responsible for torsade de pointes (TdP) in the chronic atrioventricular block dog model, known for its high susceptibility for TdP. BACKGROUND: The mechanism of TdP arrhythmias has been under debate for many years. Focal activity as well as re-entry have both been mentioned in the initiation and the perpetuation of TdP. METHODS: In 5 TdP-sensitive chronic atrioventricular block dogs, 56 needle electrodes were evenly distributed transmurally to record 240 unipolar local electrograms simultaneously...
December 26, 2017: JACC. Clinical Electrophysiology
https://www.readbyqxmd.com/read/29759788/novel-extravascular-defibrillation-configuration-with-a-coil-in-the-substernal-space-the-asd-clinical-study
#4
Joseph Y S Chan, Jacek Lelakowski, Francis D Murgatroyd, Lucas V Boersma, Jian Cao, Vladimir Nikolski, Griet Wouters, Mark C S Hall
OBJECTIVES: This study assessed the defibrillation efficacy of the substernal-lateral electrode configuration. BACKGROUND: Subcutaneous implantable cardioverter-defibrillators (ICDs) are regarded as alternatives to transvenous ICDs in certain subjects. However, substantially higher shock energy of up to 80 J may be required. Proposed is a new defibrillation method of placing the shock coil into the substernal space. METHODS: This prospective, nonrandomized, feasibility study was conducted in subjects scheduled for midline sternotomy or implant of ICD...
August 2017: JACC. Clinical Electrophysiology
https://www.readbyqxmd.com/read/29759616/spatial-relationships-of-complex-fractionated-atrial-electrograms-and-continuous-electrical-activity-to-focal-electrical-sources-implications-for-substrate-ablation-in-human-atrial-fibrillation
#5
Simon Kochhäuser, Atul Verma, Rupin Dalvi, Adrian Suszko, Pouria Alipour, Prashanthan Sanders, Jean Champagne, Laurent Macle, Girish M Nair, Hugh Calkins, David J Wilber, Vijay S Chauhan
OBJECTIVES: This study sought to evaluate the spatial relationships of focal electrical sources (FSs) to complex fractionated atrial electrograms (CFAE) and continuous electrical activity (CEA). BACKGROUND: Fractionated atrial electrograms have been associated with atrial fibrillation (AF) drivers in computational studies and represent ablation targets in the management of persistent AF. METHODS: We included a subset of 66 patients (age: 63 [56, 67] years, 69% persistent AF) with electroanatomic data from the SELECT AF (Selective complex fractionated atrial electrograms targeting for atrial fibrillation) randomized control trial that compared the efficacy of CFAE with CEA ablation in AF patients undergoing pulmonary vein antral ablation...
November 2017: JACC. Clinical Electrophysiology
https://www.readbyqxmd.com/read/29759494/impact-of-lowering-irrigation-flow-rate-on-atrial-lesion-formation-in-thin-atrial-tissue-preliminary-observations-from-experimental-and-clinical-studies
#6
Saurabh Kumar, Jorge Romero, William G Stevenson, Lori Foley, Ryan Caulfield, Akira Fujii, Shinichi Tanigawa, Laurence M Epstein, Bruce A Koplan, Usha B Tedrow, Roy M John, Gregory F Michaud
OBJECTIVES: The authors sought to investigate the effect of low irrigation flow rate on lesion characteristics and ablation outcomes in a clinicopathological study. BACKGROUND: Irrigated ablation produces deeper lesions compared with nonirrigated ablation, which may not be desirable in the thin-walled posterior left atrium (LA), where collateral esophageal injury is possible. METHODS: Lesions were placed on the smooth posterior right atrium in 20 swine and posterior LA in 60 patients at a maximum power of 20 to 25 W with either: 1) power-controlled ablation at an irrigation flow rate of 17 ml/min (high-flow group 10 swine; n = 40) or 2) temperature-controlled ablation at an irrigation flow rate of 2 ml/min (low-flow group 10 swine; n = 20)...
October 2017: JACC. Clinical Electrophysiology
https://www.readbyqxmd.com/read/29753687/istaroxime-a-positive-inotropic-agent-devoid-of-proarrhythmic-properties-in-sensitive-chronic-atrioventricular-block-dogs
#7
Alexandre Bossu, Amée Kostense, Henriette D M Beekman, Marien J C Houtman, Marcel A G van der Heyden, Marc A Vos
Current inotropic agents in heart failure therapy associate with low benefit and significant adverse effects, including ventricular arrhythmias. Istaroxime, a novel Na+ /K+ -transporting ATPase inhibitor, also stimulates SERCA2a activity, which would confer improved inotropic and lusitropic properties with less proarrhythmic effects. We investigated hemodynamic, electrophysiological and potential proarrhythmic and antiarrhythmic effects of istaroxime in control and chronic atrioventricular block (CAVB) dogs sensitive to drug-induced Torsades de Pointes arrhythmias (TdP)...
May 10, 2018: Pharmacological Research: the Official Journal of the Italian Pharmacological Society
https://www.readbyqxmd.com/read/29749578/the-relationship-between-the-p-wave-and-local-atrial-electrogram-in-predicting-conduction-block-during-catheter-ablation-of-cavo-tricuspid-isthmus-dependent-atrial-flutter
#8
Miki Yokokawa, Mohamad C Sinno, Mohammed Saeed, Rakesh Latchamsetty, Hamid Ghanbari, Thomas Crawford, Krit Jongnarangsin, Ryan Cunnane, Frank Pelosi, Frank Bogun, Aman Chugh, Fred Morady, Hakan Oral
PURPOSE: The endpoint for radiofrequency catheter ablation (RFA) of cavo-tricuspid isthmus (CTI)-dependent atrial flutter (AFL) is complete conduction block along the CTI. The purpose of this study is to evaluate the utility of the temporal relationship between the P wave and the local atrial electrograms in determining complete CTI block. METHODS: RFA of CTI was performed in 125 patients (age 63 ± 11 years). During pacing from the coronary sinus (CS), the intervals from the peak of the P wave (Ppeak ) in lead V1 to the second component of the local atrial electrogram (A2 ) along the ablation line (Ppeak -A2 ) and from the end of the P wave (Pend ) to A2 (Pend -A2 ) were investigated before and after complete block in the first 100 patients (training set)...
May 11, 2018: Journal of Interventional Cardiac Electrophysiology: An International Journal of Arrhythmias and Pacing
https://www.readbyqxmd.com/read/29724033/force-trends-and-pulsatility-for-catheter-contact-identification-in-intracardiac-electrograms-during-arrhythmia-ablation
#9
David Rivas-Lalaleo, Sergio Muñoz-Romero, Mónica Huerta, Mayra Erazo-Rodas, Juan José Sánchez-Muñoz, José Luis Rojo-Álvarez, Arcadi García-Alberola
The intracardiac electrical activation maps are commonly used as a guide in the ablation of cardiac arrhythmias. The use of catheters with force sensors has been proposed in order to know if the electrode is in contact with the tissue during the registration of intracardiac electrograms (EGM). Although threshold criteria on force signals are often used to determine the catheter contact, this may be a limited criterion due to the complexity of the heart dynamics and cardiac vorticity. The present paper is devoted to determining the criteria and force signal profiles that guarantee the contact of the electrode with the tissue...
May 2, 2018: Sensors
https://www.readbyqxmd.com/read/29721112/what-factors-lead-to-the-acceleration-of-ventricular-tachycardia-during-antitachycardia-pacing-results-from-over-1000-episodes
#10
Yin Fang, Kai Gu, Bing Yang, Weizhu Ju, Hongwu Chen, Mingfang Li, Hailei Liu, Jiaxian Wang, Gang Yang, Minglong Chen
Introduction: Ventricular tachycardia (VT) acceleration due to antitachycardia pacing (ATP) therapy could be often observed in patients with implantable cardioverter defibrillator (ICD), which usually results in additional shock. However, few studies focused on the risk factors for VT acceleration caused by ATP therapy. The purpose of this study was to investigate risk factors for VT acceleration due to ATP delivery. Methods: We retrospectively reviewed 1056 ATP episodes in 33 patients with structural heart diseases, of whom clinical characteristics and episodes details were evaluated...
February 2018: Journal of Arrhythmia
https://www.readbyqxmd.com/read/29721110/use-of-microelectrode-near-field-signals-to-determine-catheter-contact
#11
Mathew R Levy, Faisal M Merchant, Jonathan J Langberg, David B Delurgio
Background: The utility of standard distal bipolar electrograms (sEGMs) for assessing catheter-tissue contact may be obscured by the presence of far-field signals. Microelectrode electrograms (mEGMs) may overcome this limitation. Methods: We compared 5 mEGM characteristics (amplitude, frequency content, temporal signal variability, presence of injury current, and amplitude differential between bipoles) with the sEGM for determining tissue contact in 20 patients undergoing ablation of typical atrial flutter...
February 2018: Journal of Arrhythmia
https://www.readbyqxmd.com/read/29720607/concurrent-micro-to-macro-cardiac-electrophysiology-in-myocyte-cultures-and-human-heart-slices
#12
Rasheda A Chowdhury, Konstantinos N Tzortzis, Emmanuel Dupont, Shaun Selvadurai, Filippo Perbellini, Chris D Cantwell, Fu Siong Ng, Andre R Simon, Cesare M Terracciano, Nicholas S Peters
The contact cardiac electrogram is derived from the extracellular manifestation of cellular action potentials and cell-to-cell communication. It is used to guide catheter based clinical procedures. Theoretically, the contact electrogram and the cellular action potential are directly related, and should change in conjunction with each other during arrhythmogenesis, however there is currently no methodology by which to concurrently record both electrograms and action potentials in the same preparation for direct validation of their relationships and their direct mechanistic links...
May 2, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29716709/management-of-electrical-storm-of-unstable-ventricular-tachycardia-in-post-myocardial-infarction-patients-a-single-centre-experience
#13
B Hygriv Rao, Mohammed Sadiq Azam, Geetesh Manik
OBJECTIVE: This is a case series of consecutive patients with past myocardial infarction presenting with Electrical Storm (ES) of unstable ventricular tachycardia (VT) treated by a protocol directed algorithm. METHODS: Management protocol involved treatment of reversible causes, ventilatory & hemodynamic support, administration of antiarrhythmic drugs (AAD) & maximally tolerated doses of beta-blockers, stellate ganglionectomy and Radiofrequency ablation (RFA) guided by Electro Anatomic Mapping (EAM)...
March 2018: Indian Heart Journal
https://www.readbyqxmd.com/read/29707362/how-to-recognize-silent-atrial-fibrillation-in-pacemakers-and-defibrillators-the-value-of-atrial-electrograms
#14
Juan Benezet-Mazuecos, Jose Manuel Rubio, José Antonio Iglesias, Juan José de la Vieja
Today's pacemakers and defibrillators include diagnostic tools for detecting and treating cardiac arrhythmias like silent atrial fibrillation as atrial high rate episodes (AHREs). This diagnostic capability is crucial to prevent the potential embolic complications this AHREs are related to. However, sometimes data retrieved from diagnostic counters may be misleading reflecting limitations of detection algorithms, which must follow mathematical rules to classify events on a beat-to-beat basis. The incorporation of stored electrograms has been an important milestone in improving the diagnostic capabilities of these devices confirming the arrhythmia diagnosis...
March 2018: Journal of Thoracic Disease
https://www.readbyqxmd.com/read/29700057/how-accurate-is-inverse-electrocardiographic-mapping-a-systematic-in-vivo-evaluation
#15
Laura R Bear, Ian J LeGrice, Gregory B Sands, Nigel A Lever, Denis S Loiselle, David J Paterson, Leo K Cheng, Bruce H Smaill
BACKGROUND: Inverse electrocardiographic mapping reconstructs cardiac electrical activity from recorded body surface potentials. This noninvasive technique has been used to identify potential ablation targets. Despite this, there has been little systematic evaluation of its reliability. METHODS: Torso and ventricular epicardial potentials were recorded simultaneously in anesthetized, closed-chest pigs (n=5), during sinus rhythm, epicardial, and endocardial ventricular pacing (70 records in total)...
May 2018: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/29688325/anatomical-hotspots-of-fractionated-electrograms-in-the-left-and-right-atrium-do-they-exist
#16
Roeliene Starreveld, Lisette J M E van der Does, Natasja M S de Groot
Aims: Targeting of complex fractionated electrograms (CFEs) in the atria is not yet beneficial in treating drug-refractory atrial fibrillation (AF). In order to gain insight into potential anatomical hotspots of fractionated electrograms, a structured literature search was performed. Methods and results: PubMed was searched for studies describing fractionation during human atrial electrophysiological measurements (n = 565), of which 36 articles described the pre-ablation distribution of fractionated electrograms for the left atrium and/or right atrium in at least four regions...
April 20, 2018: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/29684187/non-invasive-epicardial-and-endocardial-electrocardiographic-imaging-for-scar-related-ventricular-tachycardia
#17
Linwei Wang, Omar A Gharbia, Saman Nazarian, B Milan Horácek, John L Sapp
Aims: Contact mapping is currently used to guide catheter ablation of scar-related ventricular tachycardia (VT) but usually provides incomplete assessment of 3D re-entry circuits and their arrhythmogenic substrates. This study investigates the feasibility of non-invasive electrocardiographic imaging (ECGi) in mapping scar substrates and re-entry circuits throughout the epicardium and endocardium. Methods and results: Four patients undergoing endocardial and epicardial mapping and ablation of scar-related VT had computed tomography scans and a 120-lead electrocardiograms, which were used to compute patient-specific ventricular epicardial and endocardial unipolar electrograms (CEGMs)...
April 18, 2018: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/29678635/high-incidence-of-occult-atrial-fibrillation-in-asian-patients-with-cryptogenic-stroke
#18
Swee-Chong Seow, Ann-Kee How, Siew-Pang Chan, Hock-Luen Teoh, Toon-Wei Lim, Devinder Singh, Wee-Tiong Yeo, Pipin Kojodjojo
BACKGROUND: Occult atrial fibrillation (AF) is not uncommon in patients with stroke. In western cohorts, insertable loop recorders (ILRs) have been shown to be the gold-standard and are cost-effective for AF detection. Anticoagulation for secondary stroke prevention is indicated if AF is detected. The incidence of occult AF among Asian patients with cryptogenic stroke is unclear. METHODS: Patients with cryptogenic stroke referred between August 2014 and February 2017 had ILRs implanted...
April 17, 2018: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
https://www.readbyqxmd.com/read/29672439/cajal-cell-counts-are-important-predictors-of-outcomes-in-drug-refractory-gastroparesis-patients-with-neurostimulation
#19
Endashaw Omer, Archana Kedar, Harsha S Nagarajarao, Yana Nikitina, Vetta Vedanarayanan, Charu Subramony, Christopher J Lahr, Thomas L Abell
BACKGROUND AND AIMS: Cajal cells serve as the pacemaker cells of the gastrointestinal tract and regulates peristalsis. On the baisis of that fact, it has been hypothesized that a decrease in Cajal cells can lead to gastroparesis and other motility issues. Treatment with medications has a limited efficacy and most resort to gastric electrical stimulation (GES) devices for symptomatic relief. We believe that the number of Cajal cells present is directly proportional to symptomatic relief with GES...
April 18, 2018: Journal of Clinical Gastroenterology
https://www.readbyqxmd.com/read/29663449/mild-hypothermia-33%C3%A2-c-increases-the-inducibility-of-atrial-fibrillation-an-in-vivo-large-animal-model-study
#20
Martin Manninger, Alessio Alogna, David Zweiker, Birgit Zirngast, Stefan Reiter, Viktoria Herbst, Heinrich Maechler, Burkert M Pieske, Frank R Heinzel, Helmut Brussee, Heiner Post, Daniel Scherr
OBJECTIVE: Application of therapeutic mild hypothermia in patients after resuscitation, often accompanied by myocardial infarction, cardiogenic shock and systemic inflammation may impact on cardiac rhythm. We therefore tested susceptibility to atrial arrhythmias during hyperthermia (HT, 40.5°C), normothermia (NT, 38.0°C) and mild hypothermia (MH, 33.0°C). METHODS: Nine healthy, anesthetized closed-chest landrace pigs were instrumented with a quadripolar stimulation catheter in the high right atrium and a decapolar catheter in the coronary sinus...
April 16, 2018: Pacing and Clinical Electrophysiology: PACE
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