keyword
MENU ▼
Read by QxMD icon Read
search

Unipolar mapping

keyword
https://www.readbyqxmd.com/read/28639747/the-effect-of-activation-rate-on-left-atrial-bipolar-voltage-in-patients-with-paroxysmal-atrial-fibrillation
#1
Steven E Williams, Nick Linton, Louisa O'Neill, James Harrison, John Whitaker, Rahul Mukherjee, Christopher A Rinaldi, Jaswinder Gill, Steven Niederer, Matthew Wright, Mark O'Neill
INTRODUCTION: Bipolar voltage is used during electroanatomic mapping to define abnormal myocardium, but the effect of activation rate on bipolar voltage is not known. We hypothesized that bipolar voltage may change in response to activation rate. By examining corresponding unipole signals we sought to determine the mechanisms of such changes. METHODS AND RESULTS: LA extrastimulus mapping was performed during CS pacing in 10 patients undergoing 1(st) time paroxysmal atrial fibrillation ablation...
June 22, 2017: Journal of Cardiovascular Electrophysiology
https://www.readbyqxmd.com/read/28553365/mini-electrodes-on-ablation-catheters-valuable-addition-or-redundant-information-insights-from-a-computational-study
#2
Stefan Pollnow, Joachim Greiner, Tobias Oesterlein, Eike M Wülfers, Axel Loewe, Olaf Dössel
Radiofrequency ablation has become a first-line approach for curative therapy of many cardiac arrhythmias. Various existing catheter designs provide high spatial resolution to identify the best spot for performing ablation and to assess lesion formation. However, creation of transmural and nonconducting ablation lesions requires usage of catheters with larger electrodes and improved thermal conductivity, leading to reduced spatial sensitivity. As trade-off, an ablation catheter with integrated mini electrodes was introduced...
2017: Computational and Mathematical Methods in Medicine
https://www.readbyqxmd.com/read/28546283/high-resolution-mapping-of-gastric-slow-wave-recovery-profiles-biophysical-model-methodology-and-demonstration-of-applications
#3
Niranchan Paskaranandavadivel, Leo K Cheng, Peng Du, Jack M Rogers, Gregory O'Grady
Slow waves play a central role in coordinating gastric motor activity. High-resolution mapping of extracellular potentials from the stomach provides spatiotemporal detail on normal and dysrhythmic slow-wave patterns. All mapping studies to date have focused exclusively on tissue activation; however, the recovery phase contains vital information on repolarization heterogeneity, the excitable gap, and refractory tail interactions, but has not been investigated. Here, we report a method to identify the recovery phase in slow-wave mapping data...
May 25, 2017: American Journal of Physiology. Gastrointestinal and Liver Physiology
https://www.readbyqxmd.com/read/28536891/myocardial-voltage-ratio-in-arrhythmogenic-right-ventricular-dysplasia-cardiomyopathy
#4
REVIEW
Andreas Müssigbrodt, Livio Bertagnolli, Elena Efimova, Jedrzej Kosiuk, Borislav Dinov, Kerstin Bode, Simon Kircher, Nikolaos Dagres, Michael Döring, Sergio Richter, Philipp Sommer, Daniela Husser, Andreas Bollmann, Gerhard Hindricks, Arash Arya
AIMS: This study aimed to analyze the influence of scar distribution between the endocardium and the epicardium in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). METHODS: Electroanatomical mapping data were derived from our ARVD/C registry. Myocardial voltage distribution between the endocardium and the epicardium was analyzed in 28 patients (18 men, 49.9 ± 13.0 years) with previous ventricular tachycardia (VT) ablation and complete right ventricular maps...
May 23, 2017: Herzschrittmachertherapie & Elektrophysiologie
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/28504840/clinical-utility-of-a-short-resting-state-mri-scan-in-differentiating-bipolar-from-unipolar-depression
#6
M Li, T Das, W Deng, Q Wang, Y Li, L Zhao, X Ma, Y Wang, H Yu, X Li, Y Meng, L Palaniyappan, T Li
OBJECTIVE: Depression in bipolar disorder (BipD) requires a therapeutic approach that is from treating unipolar major depressive disorder (UniD), but to date, no reliable methods could separate these two disorders. The aim of this study was to establish the clinical validity and utility of a non-invasive functional MRI-based method to classify BipD from UniD. METHOD: The degree of connectivity (degree centrality or DC) of every small unit (voxel) with every other unit of the brain was estimated in 22 patients with BipD and 22 age, gender, and depressive severity-matched patients with UniD and 22 healthy controls...
May 15, 2017: Acta Psychiatrica Scandinavica
https://www.readbyqxmd.com/read/28500175/spatial-resolution-requirements-for-accurate-identification-of-drivers-of-atrial-fibrillation
#7
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/28479513/epicardial-endocardial-breakthrough-during-stable-atrial-macroreentry-evidence-from-ultra-high-resolution-3-dimensional-mapping
#8
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 atrial fibrillation who may also have focal activations. OBJECTIVE: The purpose of this study was to investigate whether EEB could be discerned during stable right atrial (RA) macroreentry using high-density high-spatial resolution 3-dimensional mapping. METHODS: Macroreentry was diagnosed using 3-dimensional mapping and entrainment...
May 4, 2017: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/28472282/right-ventricular-outflow-tract-high-density-endocardial-unipolar-voltage-mapping-in-patients-with-brugada-syndrome-evidence-for-electroanatomical-abnormalities
#9
Konstantinos P Letsas, Michael Efremidis, Konstantinos Vlachos, Stamatis Georgopoulos, Nikolaos Karamichalakis, Dimitrios Asvestas, Kosmas Valkanas, Panagiotis Korantzopoulos, Tong Liu, Antonios Sideris
Aims: Epicardial structural abnormalities at the right ventricular outflow tract (RVOT) may provide the arrhythmia substrate in Brugada syndrome (BrS). Electroanatomical endocardial unipolar voltage mapping is an emerging tool that accurately identifies epicardial abnormalities in different clinical settings. This study investigated whether endocardial unipolar voltage mapping of the RVOT detects electroanatomical abnormalities in patients with BrS. Methods and results: Ten asymptomatic patients (8 males, 34...
May 2, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/28386822/rapid-mapping-and-differentiation-in-ventricular-outflow-tract-arrhythmia-using-non-contact-mapping
#10
Kazuo Miyazawa, Marehiko Ueda, Yusuke Kondo, Tomohiko Hayashi, Miyo Nakano, Masayuki Ishimura, Masahiro Nakano, Yoshio Kobayashi
PURPOSE: Ventricular outflow tract arrhythmias (VOTAs) can be successfully treated by catheter ablation. However, it is sometimes difficult to differentiate the origin of VOTAs between the right ventricular outflow tract (RVOT) and the other sites, leading to a long fluoroscopy time and unnecessary radiofrequency applications. This study aimed to clarify distinguishable characteristics of the propagation pattern obtained from non-contact mapping (NCM) for VOTA ablation. METHODS: Consecutive 45 patients with VOTAs who underwent catheter ablation using the NCM system were included in this study...
April 6, 2017: Journal of Interventional Cardiac Electrophysiology: An International Journal of Arrhythmias and Pacing
https://www.readbyqxmd.com/read/28371837/characterization-of-the-arrhythmogenic-substrate-in-patients-with-arrhythmogenic-right-ventricular-cardiomyopathy-undergoing-ventricular-tachycardia-ablation
#11
Senthil Kirubakaran, Caterina Bisceglia, John Silberbauer, Teresa Oloriz, Giulia Santagostino, Miki Yamase, Giuseppe Maccabelli, Nicola Trevisi, Paolo Della Bella
Aims: Arrhythmogenic right ventricular (RV) cardiomyopathy (ARVC) is associated with ventricular arrhythmias, even without RV structural disease. We aimed to characterize the RV substrate using electroanatomical mapping and to define outcomes following ventricular tachycardia (VT) ablation in patients with and without RV structural abnormalities. Methods and results: Twenty-nine patients with definite or suspected ARVC undergoing VT ablation were classified as 'electrical' and 'structural' cardiomyopathy based on the absence or presence of major structural criteria...
March 20, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/28321025/one-year-success-rate-of-pulmonary-vein-isolation-using-a-novel-irrigated-multipolar-mapping-and-ablation-catheter-with-reduced-power-settings
#12
Dong-In Shin, Jan-Erik Guelker, Christian Blockhaus, Jan Schmidt, Muhammed Kurt, Lukas Clasen, Patrick Mueller, Lars Bansemir, Christoph Brinkmeyer, Alexander Bufe, Malte Kelm, Hisaki Makimoto
The use of a novel irrigated multipolar ablation and mapping catheter for pulmonary vein isolation in patients with atrial fibrillation (AF) has demonstrated reasonable acute success rates and short procedure times, however, long-term outcome data are limited. The aim of this study was to analyze the long-term efficacy of this novel ablation system utilizing a reduced power setting for safety purposes.A total of 89 patients with paroxysmal (63 of 89 patients; 71%) or persistent AF underwent PVI with a reduced power setting of maximum 20 Watts (W) unipolar radiofrequency energy and 30 seconds in duration...
April 6, 2017: International Heart Journal
https://www.readbyqxmd.com/read/28269147/electrocardiogram-reconstruction-from-high-resolution-voltage-optical-mapping
#13
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/28236155/cardiac-magnetic-resonance-imaging-and-electroanatomic-voltage-discordance-in-non-ischemic-left-ventricle-ventricular-tachycardia-and-premature-ventricular-depolarizations
#14
Brian P Betensky, Wei Dong, Benjamin A D'Souza, Erica S Zado, Yuchi Han, Francis E Marchlinski
PURPOSE: Magnetic resonance imaging (MRI) with late gadolinium enhancement is commonly performed in patients with non-ischemic LV ventricular tachycardia/ventricular premature depolarizations (non-ischemic LV-VT/VPDs) to define VT substrate prior to catheter ablation. We investigated the prevalence of abnormal voltage and VT localized to areas of the myocardium not reported to have late gadolinium enhancement (LGE) on routine pre-procedural MRI and sought to determine if quantitative MRI analysis could reduce this discordance...
June 2017: Journal of Interventional Cardiac Electrophysiology: An International Journal of Arrhythmias and Pacing
https://www.readbyqxmd.com/read/28227376/electrocardiogram-reconstruction-from-high-resolution-voltage-optical-mapping
#15
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/28185348/two-independent-mapping-techniques-identify-rotational-activity-patterns-at-sites-of-local-termination-during-persistent-atrial-fibrillation
#16
Mahmood Alhusseini, David Vidmar, Gabriela L Meckler, Christopher A Kowalewski, Fatemah Shenasa, Paul J Wang, Sanjiv M Narayan, Wouter-Jan Rappel
INTRODUCTION: The mechanisms for atrial fibrillation (AF) are unclear in part because diverse mapping techniques yield diverse maps, ranging from stable organized sources to highly disordered waves. We hypothesized that AF mechanisms may be clarified if mapping techniques were compared in the same patients, and referenced to a clinical endpoint. We compared two independent AF mapping techniques in patients in whom ablation terminated persistent AF before pulmonary vein isolation (PVI)...
June 2017: Journal of Cardiovascular Electrophysiology
https://www.readbyqxmd.com/read/28120237/hibernating-substrate-of-ventricular-tachycardia-a-three-dimensional-metabolic-and-electro-anatomic-assessment
#17
Ayman A Hussein, Michelle Niekoop, Vasken Dilsizian, Yousra Ghzally, Mohammed Abdulghani, Ramazan Asoglu, Wengen Chen, Mark Smith, Vincent See, Stephen R Shorofsky, Timm-Michael Dickfeld
PURPOSE: Hibernating myocardium (HM) is associated with sudden cardiac death (SCD). Little is known about the electrophysiological properties of HM and the basis of its association with SCD. We aimed to electrophysiologically characterize HM in patients with ventricular tachycardia (VT). METHODS: Endocardial voltage mapping, metabolic (18)FDG-positron emission tomography (PET) and perfusion (82)Rb, (201)Tl, or (99m)Tc scans were performed in 61 ischemic heart disease patients with VT...
January 25, 2017: Journal of Interventional Cardiac Electrophysiology: An International Journal of Arrhythmias and Pacing
https://www.readbyqxmd.com/read/28108548/the-effect-of-left-ventricular-pacing-on-transmural-activation-delay-in-myopathic-human-hearts
#18
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/28011584/effect-of-anisotropy-on-ventricular-vulnerability-to-unidirectional-block-and-reentry-by-single-premature-stimulation-during-normal-sinus-rhythm-in-rat-heart
#19
S Rossi, A Buccarello, P R Ershler, R L Lux, S Callegari, D Corradi, L Carnevali, A Sgoifo, M Miragoli, E Musso, E Macchi
Single high-intensity premature stimuli when applied to the ventricles during ventricular drive of an ectopic site, as in Winfree's "pinwheel experiment," usually induce reentry arrhythmias in the normal heart, while single low-intensity stimuli barely do. Yet ventricular arrhythmia vulnerability during normal sinus rhythm remains largely unexplored. With a view to define the role of anisotropy on ventricular vulnerability to unidirectional conduction block and reentry, we revisited the pinwheel experiment with reduced constraints in the in situ rat heart...
March 1, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27932238/gender-differences-in-patients-with-arrhythmogenic-right-ventricular-dysplasia-cardiomyopathy-clinical-manifestations-electrophysiological-properties-substrate-characteristics-and-prognosis-of-radiofrequency-catheter-ablation
#20
Chin-Yu Lin, Fa-Po Chung, Yenn-Jiang Lin, Shih-Lin Chang, Li-Wei Lo, Yu-Feng Hu, Ta-Chuan Tuan, Tze-Fan Chao, Jo-Nan Liao, Yao-Ting Chang, Yun-Yu Chen, Rohit Walia, Abigail Louise D Te, Shinya Yamada, Shih-Ann Chen
BACKGROUND: Gender differences in the penetrance and clinical expression of genetic mutations have been reported in patients with arrhythmogenic right ventricular (RV) dysplasia/cardiomyopathy (ARVD/C). Our study aimed at clarifying the impact of gender on ventricular substrates and clinical outcomes after radiofrequency catheter ablation (RFCA). METHODS: Patients with ARVD/C underwent RFCA for drug-refractory ventricular arrhythmias (VAs) were consecutively enrolled...
January 15, 2017: International Journal of Cardiology
keyword
keyword
32046
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"