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pace mapping

Zhilin Qu, Michael B Liu, Michael Nivala
Intracellular calcium (Ca(2+)) alternans is a dynamical phenomenon in ventricular myocytes, which is linked to the genesis of lethal arrhythmias. Iterated map models of intracellular Ca(2+) cycling dynamics in ventricular myocytes under periodic pacing have been developed to study the mechanisms of Ca(2+) alternans. Two mechanisms of Ca(2+) alternans have been demonstrated in these models: one relies mainly on fractional sarcoplasmic reticulum Ca(2+) release and uptake, and the other on refractoriness and other properties of Ca(2+) sparks...
October 20, 2016: Scientific Reports
Bryce A Richardson, Lindsay Chaney, Nancy L Shaw, Shannon M Still
Rising temperatures have begun to shift flowering time, but it is unclear whether phenotypic plasticity can accommodate projected temperature change for this century. Evaluating clines in phenological traits and the extent and variation in plasticity can provide key information on assessing risk of maladaptation and developing strategies to mitigate climate change. In this study, flower phenology was examined in 52 populations of big sagebrush (Artemisia tridentata) growing in three common gardens. Flowering date (anthesis) varied 91 days from late July to late November among gardens...
October 14, 2016: Global Change Biology
Tobias Opthof, Carol Ann Remme, Esther Jorge, Francisco Noriega, Rob F Wiegerinck, Arlin Tasiam, Leander Beekman, Jesus Alvarez-Garcia, Cristian Munoz-Guijosa, Ruben Coronel, Juan Cinca
BACKGROUND: The repolarization pattern of the human heart is unknown. OBJECTIVE: We performed a multisite analysis of the activation-repolarization patterns and mRNA expression patterns of ion channel subunits in isolated human hearts. METHODS: Hearts from three donors without reported cardiac disease were Langendorff perfused with the patient's own blood. A standard ECG was obtained prior to explantation. Up to 92 unipolar electrograms from 24 transmural needles were obtained during right atrial pacing...
October 10, 2016: Heart Rhythm: the Official Journal of the Heart Rhythm Society
Bingbo Hou, Lihui Zheng, Guodong Niu, Lingmin Wu, Yu Qiao, Wei Sun, Ligang Ding, Gang Chen, Shu Zhang, Reginald Liew, Yan Yao
AIMS: This study was aimed to report the characteristics and treatment of ventricular tachycardia (VT) following surgical treatment of pulmonary stenosis with intact ventricular septum. METHODS AND RESULTS: Five patients underwent radiofrequency catheter ablation for sustained monomorphic left bundle branch block (LBBB) type VT who previously underwent surgical treatment of pulmonary stenosis. Except stimulation, voltage and activation mapping was performed using three-dimensional (3D) electro-anatomic mapping and ablation was applied accordingly...
October 12, 2016: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
Ana M Daugherty, Naftali Raz
Age-related declines in spatial navigation are associated with deficits in procedural and episodic memory and deterioration of their neural substrates. For the lack of longitudinal evidence, the pace and magnitude of these declines and their neural mediators remain unclear. Here we examined virtual navigation in healthy adults (N=213, age 18-77 years) tested twice, two years apart, with complementary indices of navigation performance (path length and complexity) measured over six learning trials at each occasion...
September 19, 2016: NeuroImage
James E M Watson, Danielle F Shanahan, Moreno Di Marco, James Allan, William F Laurance, Eric W Sanderson, Brendan Mackey, Oscar Venter
Humans have altered terrestrial ecosystems for millennia [1], yet wilderness areas still remain as vital refugia where natural ecological and evolutionary processes operate with minimal human disturbance [2-4], underpinning key regional- and planetary-scale functions [5, 6]. Despite the myriad values of wilderness areas-as critical strongholds for endangered biodiversity [7], for carbon storage and sequestration [8], for buffering and regulating local climates [9], and for supporting many of the world's most politically and economically marginalized communities [10]-they are almost entirely ignored in multilateral environmental agreements...
September 3, 2016: Current Biology: CB
Anandika Dhaliwal, Matthew Brenner, Paul Wolujewicz, Zheng Zhang, Yong Mao, Mona Batish, Joachim Kohn, Prabhas V Moghe
: A predictive framework for the evolution of stem cell biology in 3-D is currently lacking. In this study we propose deep image informatics of the nuclear biology of stem cells to elucidate how 3-D biomaterials steer stem cell lineage phenotypes. The approach is based on high content imaging informatics to capture minute variations in the 3-D spatial organization of splicing factor SC-35 in the nucleoplasm as a marker to classify emergent cell phenotypes of human mesenchymal stem cells (hMSCs)...
November 2016: Acta Biomaterialia
Fady Dawoud, Karl H Schuleri, David D Spragg, B Milan Horáček, Ronald D Berger, Henry R Halperin, Albert C Lardo
INTRODUCTION: The interplay between electrical activation and mechanical contraction patterns is hypothesized to be central to reduced effectiveness of cardiac resynchronization therapy (CRT). Furthermore, complex scar substrates render CRT less effective. We used novel cardiac computed tomography (CT) and noninvasive electrocardiographic imaging (ECGI) techniques in an ischemic dyssynchronous heart failure (DHF) animal model to evaluate electrical and mechanical coupling of cardiac function, tissue viability, and venous accessibility of target pacing regions...
August 30, 2016: Journal of Cardiovascular Electrophysiology
I Tan, B Spronck, T Delhaas, K Reesink, H Kiat, E Barin, M Butlin, A Avolio
OBJECTIVE: Aortic stiffness, as measured by carotid-femoral pulse wave velocity (cfPWV), is an independent marker for cardiovascular morbidity and mortality, but is dependent on blood pressure (BP) and possibly heart rate (HR). Acute HR changes are often accompanied by increased BP. This presents the need to quantify the BP-independent effect of HR on cfPWV. DESIGN AND METHOD: Individuals (n = 52, age 40-93 years, 11 female) with in situ cardiac pacemakers were paced at 60, 70, 80, 90 and 100 bpm with BP and cfPWV measured at each pacing step...
September 2016: Journal of Hypertension
Tinen L Iles, Brian Howard, Stephen Howard, Stephen Quallich, Christopher Rolfes, Eric Richardson, Hanna R Iaizzo, Paul A Iaizzo
To date, many pharmacological agents used to treat or prevent arrhythmias in open-heart cases create undesired systemic side effects. For example, antiarrhythmic drugs administered intravenously can produce drops in systemic pressure in the already compromised cardiac patient. While performing open-heart procedures, surgeons will often either create a small port or form a pericardial cradle to create suitable fields for operation. This access yields opportunities for target pharmacological delivery (antiarrhythmic or ischemic preconditioning agents) directly to the myocardial tissue without undesired side effects...
2016: Journal of Visualized Experiments: JoVE
Julien Grondin, Alexandre Costet, Ethan Bunting, Alok Gambhir, Hasan Garan, Elaine Wan, Elisa E Konofagou
BACKGROUND: Accurate determination of regional areas of arrhythmic triggers is of key interest to diagnose arrhythmias and optimize their treatment. Electromechanical wave imaging (EWI) is an ultrasound technique that can image the transient deformation in the myocardium after electrical activation and therefore has the potential to detect and characterize location of triggers of arrhythmias. OBJECTIVES: The objectives of this study were to investigate the relationship between the electromechanical and the electrical activation of the left ventricular (LV) endocardial surface during epicardial and endocardial pacing and during sinus rhythm as well as to map the distribution of electromechanical delays...
August 4, 2016: Heart Rhythm: the Official Journal of the Heart Rhythm Society
Robert S Kelley, Michael D Vardy, Grant Simons, Henry Chen, Charles Ascher-Walsh, Michael Brodman
AIMS: This is a pilot study to evaluate the feasibility of using diagnostic cardiac electrophysiology catheters for recording intrinsic urinary bladder electrical activity and for electrical pacing capture of bladder tissue. METHODS: During cystoscopy, a curved quadripolar catheter was introduced and contact was made with the right and left halves of the dome and trigone in adult female patients undergoing cystoscopy. Electrical activity was recorded, using a commercially available cardiac electrophysiologic recording system, before and during pacing at 0...
August 5, 2016: Neurourology and Urodynamics
Riccardo Proietti, Santiago Rivera, Charles Dussault, Vidal Essebag, Martin L Bernier, Felix Ayala-Paredes, Mariano Badra-Verdu, Jean-François Roux
AIMS: Ventricular arrhythmias (VA) originating from a papillary muscle (PM) have recently been described as a distinct clinical entity with peculiar features that make its treatment with catheter ablation challenging. Here, we report our experience using an intracardiac echo-facilitated 3D electroanatomical mapping approach in a case series of patients undergoing ablation for PM VA. METHODS AND RESULTS: Sixteen patients who underwent catheter ablation for ventricular tachycardia (VT) or symptomatic premature ventricular contractions originating from left ventricular PMs were included in the study...
August 2, 2016: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
Hugo Talbot, Federico Spadoni, Christian Duriez, Maxime Sermesant, Mark O'Neill, Pierre Jaïs, Stéphane Cotin, Hervé Delingette
Recent progress in cardiac catheterization and devices has allowed the development of new therapies for severe cardiac diseases like arrhythmias and heart failure. The skills required for such interventions are very challenging to learn, and are typically acquired over several years. Virtual reality simulators may reduce this burden by allowing trainees to practice such procedures without risk to patients. In this paper, we propose the first training system dedicated to cardiac electrophysiology, including pacing and ablation procedures...
July 9, 2016: Medical Image Analysis
Prakriti Gaba, Christopher V DeSimone, Benhur D Henz, Paul A Friedman, Charles J Bruce, David R Holmes, Malini Madhavan, Krithika Vasudevan, Douglas Wahnschaffe, Steven Berhow, Andrew J Danielsen, Dorothy J Ladewig, Susan B Mikell, Susan B Johnson, Scott H Suddendorf, Tomas Kara, Gregory A Worrell, Samuel J Asirvatham
OBJECTIVE: Pharmacotherapy for epilepsy is limited with 30% of patients refractory to this approach of suppressing seizures. Current surgical options are invasive and carry significant morbidities including infection, bleeding, and the potential for deleterious neurocognitive effects. As a result, there is a burgeoning need for innovation to develop safer and efficacious interventions. METHODS: Four distinct catheters (2 existing: Cardima catheter, Standard EPT Blazer catheter; 2 new prototypes: balloon catheter, basket catheters) were tested in 12 baboons (21-30 kg, 100% male)...
June 2016: Journal of Neurology & Neurophysiology
Zahra Faraji-Dana, Fred Tam, J Jean Chen, Simon J Graham
Prospective motion correction is a promising candidate solution to suppress the effects of head motion during fMRI, ideally allowing the imaging plane to remain fixed with respect to the moving head. Residual signal artifacts may remain, however, because head motion in relation to a fixed multi-channel receiver coil (with non-uniform sensitivity maps) can potentially introduce unwanted signal variations comparable to the weak fMRI BOLD signal (~1%-4% at 1.5-3.0T). The present work aimed to investigate the magnitude of these residual artifacts, and characterize the regime over which prospective motion correction benefits from adjusting sensitivity maps to reflect relative positional change between the head and the coil...
October 2016: Magnetic Resonance Imaging
Elad Anter, Cory M Tschabrunn, Alfred E Buxton, Mark E Josephson
BACKGROUND: In vivo description of ventricular tachycardia (VT) circuits is limited by insufficient spatiotemporal resolution. We used a novel high-resolution mapping technology to characterize the electrophysiological properties of the postinfarction reentrant VT circuit. METHODS: In 15 swine, myocardial infarction was induced by left anterior descending artery balloon occlusion. Animals were studied 6 to 8 weeks after myocardial infarction. Activation mapping of VTs was performed by using the Rhythmia mapping system...
July 26, 2016: Circulation
Yong Deng, Ling-Xiao Chen, Bang-Xing Han, Ding-Tao Wu, Kit-Leong Cheong, Nai-Fu Chen, Jing Zhao, Shao-Ping Li
Qualitative and quantitative analysis of specific polysaccharides from ten batches of Dendrobium huoshanense were performed using high performance size exclusion chromatography coupled with multi-angle laser light scattering and refractive index detector (HPSEC-MALLS-RID), gas chromatography-mass spectrometry (GC-MS), nuclear magnetic resonance (NMR) and saccharide mapping based on polysaccharides analysis by using carbohydrate gel electrophoresis (PACE) and high performance thin layer chromatography (HPTLC)...
September 10, 2016: Journal of Pharmaceutical and Biomedical Analysis
Bahij Kreidieh, Moisés Rodríguez-Mañero, Paul A Schurmann, Sergio Hugo Ibarra-Cortez, Amish S Dave, Miguel Valderrábano
BACKGROUND: Radiofrequency ablation (RFA) of ventricular tachycardia (VT) can fail because of inaccessibility to the VT substrate. Transarterial coronary ethanol ablation can be effective but entails arterial instrumentation risk. We hypothesized that retrograde coronary venous ethanol ablation can be an alternative bail-out approach to failed VT RFA. METHODS AND RESULTS: Out of 334 consecutive patients undergoing VT/premature ventricular contraction ablation, 7 patients underwent retrograde coronary venous ethanol ablation...
July 2016: Circulation. Arrhythmia and Electrophysiology
Hung-Ta Wo, Feng-Ching Liao, Po-Cheng Chang, Chung-Chuan Chou, Ming-Shien Wen, Chun-Chieh Wang, San-Jou Yeh
BACKGROUND: Radiofrequency catheter ablation (RFCA) of ventricular arrhythmias (VAs) originating from the left ventricular (LV) papillary muscles (PMs) is challenging. METHODS: We enrolled 16 consecutive patients who received RFCA for VAs from LV PMs. Three-dimensional electroanatomical mapping was used to construct activation and/or pace maps. RFCA was performed first at the earliest activation site or at the best matched site in the pace maps. When an acceleration or reduction in the incidence of VAs was observed during the first few seconds of the application, the ablation energy was delivered continuously for 60-120s...
October 1, 2016: International Journal of Cardiology
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