103 results found
Roney CH, Tzortzis KN, Cantwell CD, et al., 2015, A Technique for Visualising Three-Dimensional Left Atrial Cardiac Activation Data in Two Dimensions with Minimal Distance Distortion, 37th Annual International Conference of the IEEE-Engineering-in-Medicine-and-Biology-Society (EMBC), Publisher: IEEE, Pages: 7296-7299, ISSN: 1557-170X
Sulkin MS, Boukens BJ, Tetlow M, et al., 2014, Mitochondrial depolarization and electrophysiological changes during ischemia in the rabbit and human heart, AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY, Vol: 307, Pages: H1178-H1186, ISSN: 0363-6135
Ng FS, Holzem KM, Koppel AC, et al., 2014, Adverse Remodeling of the Electrophysiological Response to Ischemia-Reperfusion in Human Heart Failure Is Associated With Remodeling of Metabolic Gene Expression, CIRCULATION-ARRHYTHMIA AND ELECTROPHYSIOLOGY, Vol: 7, Pages: 875-U234, ISSN: 1941-3149
Ng FS, Debney MT, Protti A, et al., 2014, 15Early pharmacological enhancement of gap junction coupling with rotigaptide reduces arrhythmia vulnerability and modulates structural remodelling in reperfused myocardial infarction., Europace, Vol: 16 Suppl 3
Survivors of myocardial infarction (MI) are at increased risk of late ventricular arrhythmias and sudden cardiac death with infarct size and scar heterogeneity as key determinants of arrhythmic risk. Current preventative strategies are limited to few, select antiarrhythmic drugs or an implantable cardioverter-defibrillator. Cardiac gap junctions (GJ) have a key role in allowing the passage of small molecules between cells and may mediate the spread of acute myocardial infarction. We hypothesised that enhancing GJ coupling in the acute phase of MI may beneficially modify the extent and pattern of necrosis and infarction acutely, thus affording a protective effect against late arrhythmogenesis.
Roney CH, Cantwell C, Siggers JH, et al., 2014, A Novel Method for Rotor Tracking Using Bipolar Electrogram Phase, Computing in Cardiology (CinC) 2014, Pages: 233-236
Assessing the location and stability of electrical rotors can help target ablation therapy for atrial fibrillation. Rotor cores can be tracked by identifying singularities in the phase of spatially distributed electrical recordings. This is routinely applied to unipolar electrogram and action potential data, but not to bipolar electrogram data, which contains local activation only. We developed and tested a technique to track phase singularities from simulated bipolar data. Bipolar electrogram phase was found to be as effective as action potential and as unipolar electrogram phase for rotor tip detection when using simulated data, suggesting that it may be used clinically as an alternative method to unipolar phase to locate rotor phase singularities in atrial fibrillation.
Sau A, Qureshi N, Roney C, et al., 2014, The influence of late-gadolinium enhanced cardiac MRI defined scar on left atrial electrophysiological properties in patients with persistent atrial fibrillation, Annual Meeting of the European-Society-of-Cardiology (ESC), Publisher: OXFORD UNIV PRESS, Pages: 780-780, ISSN: 0195-668X
Sau A, Qureshi N, Bai W, et al., 2014, Late-gadolinium enhanced cardiac MRI defined scar is predominantly located on the left atrial septum and posterior wall in patients with persistent atrial fibrillation, Annual Meeting of the European-Society-of-Cardiology (ESC), Publisher: OXFORD UNIV PRESS, Pages: 799-799, ISSN: 0195-668X
Roney CH, Cantwell C, Qureshi NA, et al., 2014, An Automated Algorithm for Determining Conduction Velocity, Wavefront Direction and Focal Source Location using a Multipolar Catheter, IEEE Engineering in Medicine and Biology Conference
Determining locations of focal arrhythmia sources and quantifying myocardial conduction velocity (CV) are two major challenges in clinical catheter ablation cases. CV, wavefront direction and focal source location can be estimated from multipolar catheter data, but currently available methods are time-consuming, limited to specific electrode configurations, and can be inaccurate. We developed automated algorithms to rapidly identify CV from multipolar catheter data with any arrangement of electrodes, whilst providing estimates of wavefront direction and focal source position, which can guide the catheter towards a focal arrhythmic source. We validated our methods using simulations on realistic human left atrial geometry. We subsequently applied them to clinically-acquired intracardiac electrogram data, where CV and wavefront direction were accurately determined in all cases, whilst focal source locations were correctly identified in 2/3 cases. Our novel automated algorithms can potentially be used to guide ablation of focal arrhythmias in real-time in cardiac catheter laboratories.
Rutledge CA, Ng FS, Sulkin MS, et al., 2014, c-Src Kinase Inhibition Reduces Arrhythmia Inducibility and Connexin43 Dysregulation After Myocardial Infarction, JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY, Vol: 63, Pages: 928-934, ISSN: 0735-1097
Hwang HJ, Ng FS, Efimov IR, 2014, Mechanisms of Atrioventricular Nodal Excitability and Propagation, Cardiac Electrophysiology: From Cell to Bedside: Sixth Edition, Pages: 275-285, ISBN: 9781455728565
Rutledge CA, Ng FS, Sulkin MS, et al., 2013, c-Src Kinase Inhibition Reduces Arrhythmia Inducibility and Connexin43 Dysregulation After Myocardial Infarction, Scientific Sessions and Resuscitation Science Symposium of the American-Heart-Association, Publisher: LIPPINCOTT WILLIAMS & WILKINS, ISSN: 0009-7322
Ng FS, Shadi IT, Peters NS, et al., 2013, Selective heart rate reduction with ivabradine slows ischaemia-induced electrophysiological changes and reduces ischaemia-reperfusion-induced ventricular arrhythmias, JOURNAL OF MOLECULAR AND CELLULAR CARDIOLOGY, Vol: 59, Pages: 67-75, ISSN: 0022-2828
Ng FS, Janks D, Wit AL, et al., 2013, Adverse impact of heart failure on the electrophysiological response to ischaemia-reperfusion in human myocardium, Spring Meeting for Clinician Scientists in Training, Publisher: ELSEVIER SCIENCE INC, Pages: 81-81, ISSN: 0140-6736
Ng FS, Janks D, Wit AL, et al., 2012, Adverse Impact of Heart Failure on the Electrophysiological Response to Ischemia-Reperfusion in Humans, CIRCULATION, Vol: 126, ISSN: 0009-7322
Debney MT, Ng FS, Lyon AR, et al., 2012, INCREASING GAP JUNCTION COUPLING WITH ROTIGAPTIDE REDUCES THE INCIDENCE OF VENTRICULAR ARRHYTHMIAS DURING REGIONAL ISCHAEMIA, Autumn Meeting of the British-Society-for-Cardiovascular-Research (BSCR), Publisher: BMJ PUBLISHING GROUP, Pages: A3-A3, ISSN: 1355-6037
Laughner JI, Ng FS, Sulkin MS, et al., 2012, Processing and analysis of cardiac optical mapping data obtained with potentiometric dyes, AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY, Vol: 303, Pages: H753-H765, ISSN: 0363-6135
Al-Aidarous SI, Roney CH, Peters FMD, et al., 2012, CONDUCTION BLOCK INDUCED BY ACIDOSIS IN HL-1 MOUSE ATRIAL MYOCYTES CAN BE REVERSED BY ADMINISTERING THE GAP JUNCTIONAL COUPLER ROTIGAPTIDE, Annual Conference of the British-Cardiovascular-Society (BCS), Publisher: B M J PUBLISHING GROUP, Pages: A66-A66, ISSN: 1355-6037
Roney CH, Ng FS, Chowdhury RA, et al., 2012, Hysteresis of cardiac action potential duration restitution occurs in the absence of calcium transient duration hysteresis - a dual optical mapping study of ex vivo rat hearts, 2nd Congress of the European-Society-of-Cardiology Council on Basic Cardiovascular Science - Frontiers in Cardiovascular Biology, Publisher: OXFORD UNIV PRESS, Pages: S63-S63, ISSN: 0008-6363
Ng FS, Cooper SA, Chowdhury RA, et al., 2011, Short-term enhancement of gap junctional coupling during early myocardial infarction modifies late susceptibility to ventricular arrhythmias, EUROPEAN HEART JOURNAL, Vol: 32, Pages: 797-797, ISSN: 0195-668X
Ng FS, Owusu-Agyei AA, Chang ETY, et al., 2010, ZP1210, a Novel Gap Junction Modulator, Attenuates Conduction Slowing and Prevents Cx43 Dephosphorylation During Metabolic Stress, American Heart Association (AHA) Scientific Sessions 2010, Pages: A13633-A13633
Owusu-Agyei AA, Ng FS, Chang ETY, et al., 2010, The gap junction modulator ZP1210 attenuates ischaemia-induced connexin43 dephosphorylation, Heart Rhythm Congress 2010, Pages: ii11-ii11
Ng FS, Lyon AR, Owusu-Agyei AA, et al., 2010, ZP1210 attenuates gap junctional uncoupling and conduction slowing in a metabolic stress model: an optical mapping study, Heart Rhythm Congress 2010, Pages: ii11-ii11
Ng FS, Lyon AR, Cooper SA, et al., 2010, Conduction slowing in the infarct border zone correlates with ventricular arrhythmia inducibility in a chronic myocardial infarction model, Heart Rhythm Congress 2010, Pages: ii10-ii10
Cooper SA, Ng FS, Chowdhury RA, et al., 2010, Heterogeneity of fibrosis in the infarct border zone correlates with arrhythmia inducibility post-myocardial infarction, Heart Rhythm Congress 2010, Pages: ii2-ii2
Ng FS, Shadi IT, Peters NS, et al., 2010, Ivabradine reduces the incidence of reperfusion ventricular fibrillation following regional ischaemia: insights into anti-arrhythmic protective effect from optical mapping, European Society of Cardiology (ESC), Pages: 1043-1043
Ng FS, Lyon AR, Shadi IT, et al., 2010, Modulation of Gap Junctional Coupling as an Anti-Arrhythmic Strategy to Prevent Reperfusion Arrhythmias, British Cardiovascular Society Annual Conference 2010, Pages: A2-A3
Ng FS, Lyon AR, Shadi IT, et al., 2010, Gap Junction Modulation - An Anti-Arrhythmic Strategy to Prevent Reperfusion VF, 31st Annual Scientific Sessions of the Heart Rhythm Society (HRS), Pages: S353-S353
Ng FS, Lyon AR, Shadi IT, et al., 2010, Moderate gap junctional uncoupling with carbenoxolone slows conduction and increases vulnerability to ventricular arrhythmias—an optical mapping study, 6th Annual Congress of the European Cardiac Arrhythmia Society (April 2010), Pages: 234-234
It is uncertain whether moderate conductionslowing through gap junctional uncoupling on its own, inthe absence of action potential or structural changes, issufficient to be pro-arrhythmic. We used optical mapping:(1) to study the effects of carbenoxolone (CBX), a gapjunction uncoupler, on conduction velocity and actionpotential duration and (2) to assess the effects of moderateconduction slowing and gap junctional uncoupling onarrhythmia vulnerability in structurally normal hearts.Methods: Rat hearts (n = 12) were perfused on aLangendorff apparatus, loaded with a voltage-sensitivedye (RH237) and perfused with an excitation–contractionuncoupler (10 μM blebbistatin). Transmembrane voltagetransients were recorded using a 256-photodiode array.Hearts were then perfused with 30 μM CBX (n=6) orcontrol (n=6) for 30 min and epicardial activation mappedevery 2 min during ventricular pacing. Subsequently, heartswere subjected to programmed ventricular stimulation andassigned an inducibility quotient depending on ease ofarrhythmia inducibility. Results: CBX slowed conductionvelocity (conduction velocity index: baseline 100%, CBX70±2%, P<0.01), with no change in control hearts after30 min (baseline 100%, controls 98±3%, P=NS). CBX didnot affect action potential duration (APD90: baseline 90±3 ms, CBX 94±5 ms, P=NS). Inducibility of ventriculararrhythmias was increased in CBX hearts compared withcontrol hearts (inducibility quotient: CBX 5.0±1.0, control2.5±1.0, P<0.05). Conclusions: Gap junctional uncouplingwith CBX produced a 30% reduction in conductionvelocity without changes in action potential duration andresulted in increased arrhythmia vulnerability. These results suggest that moderate conduction slowing produced by gap junctional uncoupling in isolation, i.e. in the absence of changes in action potential duration or structural abnormalities, is sufficient to increase susceptibility to ventricular arrhythmias.
Nicholson-Thomas D, Chowdhury RA, Ng FS, et al., 2010, A novel approach to visualising three-dimensional connexin43 distribution in a rat infarct model, 6th Annual Congress of the European Cardiac Arrhythmia Society, Pages: 172-173
Chang ETY, Ng FS, Chowdhury RA, et al., 2010, Carbenoxolone limits increase in Connexin43 expression in ischaemic rat ventricular tissue, 6th Annual Congress of the European Cardiac Arrhythmia Society, Pages: 234-235
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