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https://www.readbyqxmd.com/read/28543823/unknown-intracardiac-electrogram
#1
Eric N Prystowsky
Watch a video presentation of this article. For additional educational resources, please visit Medtronic Academy .
May 2017: Journal of Cardiovascular Electrophysiology
https://www.readbyqxmd.com/read/28543788/automated-verification-of-pulmonary-vein-isolation-in-radiofrequency-and-cryoballoon-guided-ablation
#2
Jan De Pooter, Thomas Phlips, Milad El Haddad, Frederic van Heuverswyn, Liesbeth Timmers, René Tavernier, Sebastien Knecht, Yves Vandekerckhove, Mattias Duytschaever
BACKGROUND: Verification of pulmonary vein isolation (PVI) can be challenging due to the coexistence of pulmonary vein potentials (PVP) and far field potentials. This study aimed to prospectively validate a novel algorithm for automated verification of PVI in radiofrequency-guided (RF) and cryoballoon-guided (CB) ablation strategies. METHODS: A dataset of 620 (RF: 516 EGMs and CB: 104 EGMs) bipolar electrograms (EGM), recorded by circular mapping catheter (CMC) placed at the left atrium-pulmonary vein (PV) junction, were prospectively analyzed by a two-step algorithm...
May 25, 2017: Pacing and Clinical Electrophysiology: PACE
https://www.readbyqxmd.com/read/28543277/experimental-study-of-cryofreezing-energy-applications-on-the-ventricular-myocardium-using-sheep-hearts
#3
Kaoru Okishige, Peter L Friedman
BACKGROUND: Cryofreezing energy has been utilized to abolish arrhythmogenic substrates of various kinds of tachyarrhythmias. However, systematic electrophysiological and histological investigations of cryothermia have never been performed. The aim of this study was to clarify those aspects using sheep beating hearts. METHODS: A total of eight adult sheep were utilized under total anesthesia, and a pericardial cradle was made by opening the pericardium. Eight epicardial plaque electrodes were sutured on the epicardial surface of the left ventricle 2∼3 cm apart from each other...
May 23, 2017: Pacing and Clinical Electrophysiology: PACE
https://www.readbyqxmd.com/read/28525921/a-new-electrogram-based-diagnostic-algorithm-to-improve-the-left-ventricular-effective-pacing-detection-corrected-a-non-response-to-cardiac-resynchronization-therapy-pacing
#4
Roberto Matía, Antonio Hernández-Madrid, Ruth Nicholson Klepfer, Subham Ghosh, Gonzalo Sánchez-Huete, Javier Moreno
No abstract text is available yet for this article.
May 1, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/28525920/torsade-de-pointes-arrhythmias-arise-at-the-site-of-maximal-heterogeneity-of-repolarization-in-the-chronic-complete-atrioventricular-block-dog
#5
Albert Dunnink, Thom R G Stams, Alexandre Bossu, Veronique M F Meijborg, Jet D M Beekman, Sofieke C Wijers, Jacques M T De Bakker, Marc A Vos
Aims: The chronic complete atrioventricular block (CAVB) dog is highly sensitive for drug-induced torsade de pointes (TdP) arrhythmias. Focal mechanisms have been suggested as trigger for TdP onset; however, its exact mechanism remains unclear. In this study, detailed mapping of the ventricles was performed to assess intraventricular heterogeneity of repolarization in relation to the initiation of TdP. Methods and results: In 8 CAVB animals, 56 needles, each containing 4 electrodes, were inserted in the ventricles...
May 1, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/28523369/-new-strategies-and-technologies-for-ablation-of-atrial-fibrillation-where-do-we-go
#6
A Metzner, J Riedl, K-H Kuck
Catheter-based ablation is an established treatment option for patients with symptomatic atrial fibrillation (AF). Pulmonary vein isolation is the established cornerstone of all ablation strategies. However, the rate of electrical reconduction of previously isolated pulmonary veins is high and associated with recurrence of AF. Novel and innovative mapping and ablation systems are being developed or are under clinical evaluation aiming for higher durability of pulmonary vein isolation. Additional ablation strategies for patients with recurrence of AF despite persistent isolation of the pulmonary veins are under evaluation...
May 18, 2017: Herz
https://www.readbyqxmd.com/read/28515003/reverse-atrial-electrical-remodeling-induced-by-cardiac-resynchronization-therapy
#7
Bryce Alexander, Fariha Sadiq, Kousha Azimi, Benedict Glover, Pavel Antiperovitch, Wilma M Hopman, Zardasht Jaff, Adrian Baranchuk
PURPOSE: Cardiac resynchronization therapy (CRT) has been shown to improve left atrial function; however the effect on reverse electrical remodeling has been poorly evaluated. We hypothesized that CRT might induce reverse atrial electrical remodeling manifesting in the surface ECG as a shortening in P-wave duration. METHODS: Patients with CRT and more than 92% biventricular pacing at minimum follow-up of 1 year were included in the analysis. Those with prior history of atrial fibrillation (AF) were excluded...
April 28, 2017: Journal of Electrocardiology
https://www.readbyqxmd.com/read/28507740/mark-josephson-pioneer-educator-and-mentor-to-a-generation-of-cardiac-electrophysiologists
#8
William G Stevenson
In January 2017 we lost a giant in cardiac electrophysiology, whose work and teachings touched all of us working in the field. Mark Josephson's early work, building on the work of Hein Wellens in using programmed stimulation and catheter mapping to understand scar-related ventricular tachycardias, led the way to surgical and then catheter ablation as a viable therapy for that arrhythmia. His seminal observations are many and catalogued in 'The Josephson School' a wonderful book with 59 Chapters and extensive commentary devoted to his research...
April 2017: Arrhythmia & Electrophysiology Review
https://www.readbyqxmd.com/read/28501100/comparison-of-direct-current-synchronized-cardioversion-to-ibutilide-guided-catheter-ablation-for-long-term-sinus-rhythm-maintenance-after-isolated-pulmonary-vein-isolation-of-persistent-atrial-fibrillation
#9
Maojing Wang, Qing Zhao, Wei Ding, Shanglang Cai
Use of the antiarrhythmic ibutilide after isolated pulmonary vein isolation (PVI) might distinguish atrial remodeling severity and cases requiring further substrate modification, thereby improving efficacy of persistent atrial fibrillation (AF) treatment. Ninety-six consecutive patients with persistent AF were randomized after PVI to either direct current synchronized cardioversion (DCC group, n = 48) or 1 mg of intravenous ibutilide (ibutilide group, n = 48) followed by no further intervention if AF converted to sinus rhythm (SR) within 30 minutes (ibutilide conversion subgroup) or by complex fractionated atrial electrogram (CFAE) ablation until SR recovery or complete CFAE elimination (ibutilide nonconversion subgroup)...
March 29, 2017: American Journal of Cardiology
https://www.readbyqxmd.com/read/28500479/-catheter-ablation-of-persistent-atrial-fibrillation-where-do-we-go
#10
C Lemeš, K-H Kuck, S Mathew
Despite the very promising initial results of clinical studies, catheter ablation of persistent atrial fibrillation (AF) remains a challenge in modern electrophysiology. On the basis of the hypothesized pathophysiological mechanisms, a variety of ablation strategies have been developed over the course of time. The current ablation strategies range from pulmonary vein isolation (PVI) alone as first-line therapy, through ablation of multiple linear lesions, ablation of complex fractionated atrial electrograms (CFAE), rotor ablation, isolation of fibrotic and scar tissue up to isolation of the left atrial appendage (LAA); however, it is unclear even to the present day whether these complex and time-consuming strategies actually improve the success rate of ablation therapy...
May 12, 2017: Herz
https://www.readbyqxmd.com/read/28500175/spatial-resolution-requirements-for-accurate-identification-of-drivers-of-atrial-fibrillation
#11
Caroline H Roney, Chris D Cantwell, Jason D Bayer, Norman A Qureshi, Phang Boon Lim, Jennifer H Tweedy, Prapa Kanagaratnam, Nicholas S Peters, Edward J Vigmond, Fu Siong Ng
BACKGROUND: Recent studies have demonstrated conflicting mechanisms underlying atrial fibrillation (AF), with the spatial resolution of data often cited as a potential reason for the disagreement. The purpose of this study was to investigate whether the variation in spatial resolution of mapping may lead to misinterpretation of the underlying mechanism in persistent AF. METHODS AND RESULTS: Simulations of rotors and focal sources were performed to estimate the minimum number of recording points required to correctly identify the underlying AF mechanism...
May 2017: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/28496076/-early-results-of-complex-fractionated-atrial-electrogram-mapping-guided-atrial-fibrillation-surgery
#12
Kazuaki Fukahara, Mari Sakai, Shigeki Yokoyama, Toshio Doi, Naoki Yoshimura
OBJECTIVE: Although the Cox-maze operation is the standard surgical procedure for permanent atrial fibrillation(AF), conversion to sinus rhythm is limited by patient characteristics, including the duration of AF, atrial size, and voltage of fibrillation waves. A surgical strategy based on structural alteration of the electrical substrates of AF is required to achieve better outcomes of AF surgery. Complex fractionated atrial electrogram (CFAE) plays an important role in the electrical substrate of AF...
May 2017: Kyobu Geka. the Japanese Journal of Thoracic Surgery
https://www.readbyqxmd.com/read/28491760/hierarchical-analysis-of-electrograms-to-guide-termination-of-persistent-atrial-fibrillation
#13
Andreu Porta-Sánchez, Andrew C T Ha, Sachin Nayyar, Rupin Dalvi, Vijay S Chauhan
No abstract text is available yet for this article.
January 2017: HeartRhythm Case Reports
https://www.readbyqxmd.com/read/28484122/effects-of-propranolol-and-verapamil-on-changes-in-tq-and-st-segment-potentials-during-graded-coronary-flow-reduction-in-a-porcine-myocardial-ischemia-model
#14
Ichiro Watanabe, Leonard S Gettes
Acute myocardial ischemia causes TQ depression and ST elevation. However, the effects of cardioprotective drugs such as β-blockers and Ca(++)-antagonists on the extent of TQ depression, ST elevation, and myocardial ischemic injury are not fully understood.We created a carotid-coronary shunt in 30 pigs, and extracellular K(+) ([K(+)]e), TQ, and ST segments were recorded simultaneously with K(+)-selective plunge electrodes placed in the left anterior descending artery (LAD) distribution during graded LAD flow reduction before and after administration of propranolol or verapamil...
May 8, 2017: International Heart Journal
https://www.readbyqxmd.com/read/28479513/epicardial-endocardial-breakthrough-during-stable-atrial-macro-reentry-evidence-from-ultra-high-resolution-three-dimensional-mapping-epicardial-endocardial-breakthrough-in-atrial-macro-reentry
#15
Bhupesh Pathik, Geoffrey Lee, Frédéric Sacher, Michel Haïssaguerre, Pierre Jaïs, Grégoire Massoullié, Nicolas Derval, Prashanthan Sanders, Peter Kistler, Jonathan M Kalman
BACKGROUND: Evidence for epicardial-endocardial breakthrough(EEB) is derived from mapping inferences in patients with AF who may also have focal activations. OBJECTIVES: We investigated whether EEB could be discerned during stable right atrial macro-reentry using high-density high-spatial resolution 3D mapping. METHODS: Macro-reentry was diagnosed using 3D mapping and entrainment. Bipolar maps were reviewed for EEB defined as (i)focal endocardial activation with radial spread unaccounted for by an endocardial wavefront and (ii)present with the same timing on every tachycardia cycle...
May 4, 2017: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/28473110/impact-of-chronic-total-coronary-occlusion-on-recurrence-of-ventricular-arrhythmias-in-ischemic-secondary-prevention-implantable-cardioverter-defibrillator-recipients-vacto-secondary-study-insights-from-coronary-angiogram-and-electrogram-analysis
#16
Luis Nombela-Franco, Mario Iannaccone, Ignasi Anguera, Ignacio J Amat-Santos, Manuel Sanchez-Garcia, Daniel Bautista, Martin N Calvelo, Andrea Di Marco, Claudio Moretti, Roberto Pozzi, Marco Scaglione, Victoria Cañadas, María Sandin-Fuentes, Angel Arenal, Rodrigo Bagur, Nicasio Perez-Castellano, Cristina Fernandez-Perez, Fiorenzo Gaita, Carlos Macaya, Javier Escaned, Ignacio Fernández-Lozano
OBJECTIVES: This study sought to evaluate the incidence and clinical effect of coronary chronic total occlusions (CTOs) in patients with ischemic cardiomyopathy receiving an implantable cardioverter-defibrillator (ICD) for secondary prevention of sudden cardiac death (SCD). BACKGROUND: CTOs are common in patients with ischemic cardiomyopathy, which is the major cause of SCD. However, the impact of CTO in SCD survivors receiving an ICD is unknown. METHODS: A total of 425 patients who had survived an episode of ventricular arrhythmias and underwent ICD implantation for secondary prevention in 8 centers were included...
May 8, 2017: JACC. Cardiovascular Interventions
https://www.readbyqxmd.com/read/28467647/prediction-of-optimal-cardiac-resynchronization-by-vectors-extracted-from-electrograms-in-dyssynchronous-canine-hearts
#17
Elien B Engels, Marc Strik, Lars B van Middendorp, Marion Kuiper, Kevin Vernooy, Frits W Prinzen
INTRODUCTION: Proper optimization of atrioventricular (AV) and interventricular (VV) intervals can improve the response to cardiac resynchronization therapy (CRT). It has been demonstrated that the area of the QRS complex (QRSarea) extracted from the vectorcardiogram can be used as a predictor of optimal CRT-device settings. We explored the possibility of extracting vectors from the electrograms (EGMs) obtained from pacing electrodes and of using these EGM-based vectors (EGMVs) to individually optimize acute haemodynamic CRT response...
May 3, 2017: Journal of Cardiovascular Electrophysiology
https://www.readbyqxmd.com/read/28461795/prolonged-sinus-pauses-upon-termination-of-paroxysmal-atrial-fibrillation-abnormal-right-atrial-electrophysiologic-and-electroanatomic-findings
#18
Zhengyu Bao, Hongwu Chen, Bing Yang, Michael Shehata, Weizhu Ju, Fengxiang Zhang, Gang Yang, Kai Gu, Mingfang Li, Kejiang Cao, Xunzhang Wang, Minglong Chen
The efficacy of pulmonary vein antral isolation for patients with prolonged sinus pauses (PSP) on termination of atrial fibrillation has been reported. We studied the right atrial (RA) electrophysiologic and electroanatomic characteristics in such patients. Forty patients underwent electroanatomic mapping of the RA: 13 had PSP (group A), 13 had no PSP (group B), and 14 had paroxysmal supraventricular tachycardia (control group C). Group A had longer P-wave durations in lead II than did groups B and C (115.5 ± 15...
April 2017: Texas Heart Institute Journal
https://www.readbyqxmd.com/read/28451774/relationship-between-left-atrium-catheter-contact-force-and-pacing-threshold
#19
Teresa Barrio-López, Mercedes Ortiz, Eduardo Castellanos, Carla Lázaro, Jefferson Salas, Sergio Madero, Jesús Almendral
PURPOSE: The purpose of this study is to analyze the relationship between contact force (CF) and pacing threshold in left atrium (LA). METHODS: Six to ten LA sites were studied in 28 consecutive patients with atrial fibrillation undergoing pulmonary vein isolation. Median CF, bipolar and unipolar electrogram voltage, impedance, and bipolar and unipolar thresholds for consistent constant capture and for consistent intermittent capture were measured at each site. RESULTS: Pacing threshold measurements were performed at 188 LA sites...
April 27, 2017: Journal of Interventional Cardiac Electrophysiology: An International Journal of Arrhythmias and Pacing
https://www.readbyqxmd.com/read/28451594/novel-biomarker-for-evaluating-ischemic-stress-using-an-electrogram-derived-phase-space
#20
Wilson W Good, Burak Erem, Jaume Coll-Font, Dana H Brooks, Rob S MacLeod
The underlying pathophysiology of ischemia is poorly understood, resulting in unreliable clinical diagnosis of this disease. This limited knowledge of underlying mechanisms suggested a data driven approach, which seeks to identify patterns in the ECG data that can be linked statistically to underlying behavior and conditions of ischemic tissue. Previous studies have suggested that an approach known as Laplacian eigenmaps (LE) can identify trajectories, or manifolds, that are sensitive to different spatiotemporal consequences of ischemic stress, and thus serve as potential clinically relevant biomarkers...
September 2016: Computing in Cardiology
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