Imperial College London

DrTomWong

Faculty of MedicineNational Heart & Lung Institute

Reader in Cardiology
 
 
 
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+44 (0)20 7351 8619tom.wong

 
 
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Dr Vias Markides +44 (0)20 7351 8619

 
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Location

 

Chelsea WingRoyal Brompton Campus

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Summary

 

Publications

Publication Type
Year
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160 results found

Gandjbakhch E, Laredo M, Berruezo A, Gourraud J-B, Sellal J-M, Martins R, Sacher F, Pison L, Pruvot E, Jáuregui B, Frontera A, Kumar S, Wong T, DellaBella P, Maury Pet al., 2021, Outcomes after catheter ablation of ventricular tachycardia without implantable cardioverter-defibrillator in selected patients with arrhythmogenic right ventricular cardiomyopathy., Europace, Vol: 23, Pages: 1428-1436

AIMS: The roles of implantable cardioverter-defibrillators (ICDs) and radiofrequency catheter ablation (RCA) in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) and well-tolerated monomorphic ventricular tachycardia (MVT) are debated. In this multicentre retrospective study, we aimed at reporting the outcome of selected patients with ARVC after RCA without a back-up ICD. METHODS AND RESULTS: Patients with ARVC who underwent RCA of well-tolerated MVT at 10 tertiary centres across 5 countries, without an ICD before and 3 months after RCA, without syncope or electrical storm, and with left ventricular ejection fraction ≥50% were included. In total, 65 ARVC patients [mean age 44.5 ± 13.2 years, 78% males] underwent RCA of MVT between 2003 and 2016. Clinical presentation was palpitations in 51 (80%) patients. One (2%) patient had >1 clinical MVT. At the ablative procedure, clinical MVTs (mean rate 185 ± 32 b.p.m.) were inducible in 50 (81%) patients. Epicardial ablation was performed in 19 (29%) patients. Complete acute success was achieved in 47 (72%) patients. After a median follow-up of 52.4 months (range 12.3-171.4), there was no death or aborted cardiac arrest, and VT recurred in 19 (29%) patients. Survival without VT recurrence was estimated at 88%, 80%, and 68%, 12, 36, and 60 months after RCA, respectively, and was significantly associated with the approach and the procedural outcome. CONCLUSION : In patients with ARVC, well-tolerated MVT without a back-up ICD did not lead to fatal arrhythmic event after RCA despite VT recurrences in some. Our data suggest that RCA may be an alternative to ICD in selected ARVC patients.

Journal article

Hind M, Wong T, 2021, Atrial Fibrillation, Obstructive Sleep Apnea, and Continuous Positive Airway Pressure: No Easy Fix., Am J Respir Crit Care Med, Vol: 204, Pages: 503-505

Journal article

Simard T, Jung RG, Lehenbauer K, Piayda K, Pracon R, Jackson GG, Flores-Umanzor E, Faroux L, Korsholm K, Chun JKR, Chen S, Maarse M, Montrella K, Chaker Z, Spoon JN, Pastormerlo LE, Meincke F, Sawant AC, Moldovan CM, Qintar M, Aktas MK, Branca L, Radinovic A, Ram P, El-Zein RS, Flautt T, Ding WY, Sayegh B, Benito-Gonzalez T, Lee O-H, Badejoko SO, Paitazoglou C, Karim N, Zaghloul AM, Agrawal H, Kaplan RM, Alli O, Ahmed A, Suradi HS, Knight BP, Alla VM, Panaich SS, Wong T, Bergmann MW, Chothia R, Kim J-S, Prado APD, Bazaz R, Gupta D, Valderrabano M, Sanchez CE, Chami MFE, Mazzone P, Adamo M, Ling F, Wang DD, O'Neill W, Wojakowski W, Pershad A, Berti S, Spoon D, Kawsara A, Jabbour G, Boersma LVA, Schmidt B, Nielsen-Kudsk JE, Rodes-Cabau J, Freixa X, Ellis CR, Fauchier L, Demkow M, Sievert H, Main ML, Hibbert B, Holmes DR, Alkhouli Met al., 2021, Predictors of Device-Related Thrombus Following Percutaneous Left Atrial Appendage Occlusion, JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY, Vol: 78, Pages: 297-313, ISSN: 0735-1097

Journal article

Shi R, Chen Z, Pope MTB, Zaman JAB, Debney M, Marinelli A, Boyalla V, Sathishkumar A, Karim N, Cantor E, Valli H, Haldar S, Jones DG, Hussain W, Markides V, Betts TR, Wong Tet al., 2021, Individualized ablation strategy to treat persistent atrial fibrillation: Core-to-boundary approach guided by charge-density mapping, HEART RHYTHM, Vol: 18, Pages: 862-870, ISSN: 1547-5271

Journal article

Ali AN, Riad O, Tawfik M, Opel A, Wong Tet al., 2021, Newer generation cryoballoon vs. contact force-sensing radiofrequency ablation catheter in the ablation of paroxysmal atrial fibrillation., Herzschrittmacherther Elektrophysiol, Vol: 32, Pages: 236-243

BACKGROUND: Catheter ablation for atrial fibrillation (AF) has become an effective treatment to control symptoms. The second generation cryoballoon (CB) was designed for more efficient and homogenous freeze. Radiofrequency (RF) ablation catheters using three-dimensional electroanatomical mapping with the use of contact-force radiofrequency (CF RF) technology has achieved good results in several studies. OBJECTIVES: To compare the efficacy and safety of second-generation CB ablation in contrast to CF RF ablation in the ablation of paroxysmal AF. METHODS: A total of 81 consecutive patients suffering from paroxysmal AF underwent pulmonary vein isolation (PVI) either by the second generation cryoballoon (n = 44) or a contact force-sensing RF catheter (n = 37). The study was conducted at Ain Shams University Hospitals and Royal Brompton & Harefield NHS trust. Baseline data, procedural data and patient follow up-at 3, 6 and 12 months-were collected and analysed. RESULTS: The mean age was 53.8 ± 15 years in the CB group and 62.4 ± 12 years in the RF group, females representing 40.9% and 48.6% respectively. The baseline characteristics were comparable, but the CB group had less left atrial diameter and more left ventricular ejection fraction. The CB procedure was shorter (94.4 ± 39.3 vs. 140.8 ± 44.3 min, p < 0.0001), with longer fluoroscopy time (30 vs. 15.1 min, p = 0.047). Procedural complications were comparable between the two groups (CB 4.6%, CF RF 2.7%, p = 0.411). After 1 year, the recurrence rate in the CB group was similar to RF (27.3% vs. 27% respectively, p = 0.980). CONCLUSION: Second-generation CB ablation of paroxysmal AF has similar efficacy and safety to contact force-sensing RF catheters, with shorter procedure times and more fluoroscopy.

Journal article

Maclean E, Simon R, Ang R, Dhillon G, Ahsan S, Khan F, Earley M, Lambiase PD, Rosengarten J, Chow AW, Dhinoja M, Providencia R, Markides V, Wong T, Hunter RJ, Behar JMet al., 2021, A multi-center experience of ablation index for evaluating lesion delivery in typical atrial flutter, PACE-PACING AND CLINICAL ELECTROPHYSIOLOGY, Vol: 44, Pages: 1039-1046, ISSN: 0147-8389

Journal article

Chen J, Yang G, Khan H, Zhang H, Zhang Y, Zhao S, Mohiaddin R, Wong T, Firmin D, Keegan Jet al., 2021, JAS-GAN: generative adversarial network based joint atrium and scar segmentations on unbalanced atrial targets, IEEE Journal of Biomedical and Health Informatics, ISSN: 2168-2194

Automated and accurate segmentation of the left atrium (LA) and atrial scars from late gadolinium-enhanced cardiac magnetic resonance (LGE CMR) images are in high demand for quantifying atrial scars. The previous quantification of atrial scars relies on a two-phase segmentation for LA and atrial scars due to their large volume difference (unbalanced atrial targets). In this paper, we propose an inter-cascade generative adversarial network, namely JAS-GAN, to segment the unbalanced atrial targets from LGE CMR images automatically and accurately in an end-to-end way. Firstly, JAS-GAN investigates an adaptive attention cascade to automatically correlate the segmentation tasks of the unbalanced atrial targets. The adaptive attention cascade mainly models the inclusion relationship of the two unbalanced atrial targets, where the estimated LA acts as the attention map to adaptively focus on the small atrial scars roughly. Then, an adversarial regularization is applied to the segmentation tasks of the unbalanced atrial targets for making a consistent optimization. It mainly forces the estimated joint distribution of LA and atrial scars to match the real ones. We evaluated the performance of our JAS-GAN on a 3D LGE CMR dataset with 192 scans. Compared with state-of-the-art methods, our proposed approach yielded better segmentation performance (Average Dice Similarity Coefficient (DSC) values of 0.946 and 0.821 for LA and atrial scars, respectively), which indicated the effectiveness of our proposed approach for segmenting unbalanced atrial targets.

Journal article

Griffiths S, Behar JM, Lascelles K, Wong Tet al., 2021, The fatal consequence of inappropriate therapy in a single VF zone primary prevention defibrillator., Pacing Clin Electrophysiol, Vol: 44, Pages: 740-743

We report a case of inappropriate implantable cardioverter defibrillator (ICD) therapy due to single ventricular fibrillation (VF) zone programming leading to patient death. A remote transmission was received from a patient with a cardiac resynchronization therapy-defibrillator showing sinus tachycardia in the VF detection zone initiating inappropriate shocks and resulting in shock refractory VF. This case report highlights the importance of manufacturer specific ICD programming. In devices without discrimination in the VF zone, a higher rate single VF detection zone and/or addition of a ventricular tachycardia zone with supraventricular tachycardia discrimination should be considered.

Journal article

Schwarzl JM, Schleberger R, Kahle A-K, Hoeller A, Schwarzl M, Schaeffer BN, Muenkler P, Moser J, Akbulak RO, Eickholt C, Dinshaw L, Dickow J, Maury P, Sacher F, Martin CA, Wong T, Estner HL, Jais P, Willems S, Meyer Cet al., 2021, Specific electrogram characteristics impact substrate ablation target area in patients with scar-related ventricular tachycardia-insights from automated ultrahigh-density mapping, JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Vol: 32, Pages: 376-388, ISSN: 1045-3873

Journal article

Ma Y, Zaman JAB, Shi R, Karim N, Panikker S, Chen Z, Chen W, Jones DG, Hussain W, Markides V, Wong Tet al., 2021, Spectral characterization and impact of stepwise ablation protocol including LAA electrical isolation on persistent AF, PACE-PACING AND CLINICAL ELECTROPHYSIOLOGY, Vol: 44, Pages: 318-326, ISSN: 0147-8389

Journal article

Boyalla V, Jarman JWE, Markides V, Hussain W, Wong T, Mead RH, Engel G, Kong MH, Patrawala RA, Winkle RAet al., 2021, Internationally validated score to predict the outcome of non-paroxysmal atrial fibrillation ablation: the 'FLAME score', OPEN HEART, Vol: 8, ISSN: 2053-3624

Journal article

Haldar S, Khan HR, Boyalla V, Kralj-Hans I, Jones S, Lord J, Onyimadu O, Satishkumar A, Bahrami T, De Souza A, Clague JR, Francis DP, Hussain W, Jarman JW, Jones DG, Chen Z, Mediratta N, Hyde J, Lewis M, Mohiaddin R, Salukhe TV, Murphy C, Kelly J, Khattar RS, Toff WD, Markides V, McCready J, Gupta D, Wong T, CASA-AF Investigatorset al., 2020, Catheter ablation vs. thoracoscopic surgical ablation in long-standing persistent atrial fibrillation: CASA-AF randomized controlled trial., European Heart Journal, Vol: 41, Pages: 4471-4480, ISSN: 0195-668X

AIMS: Long-standing persistent atrial fibrillation (LSPAF) is challenging to treat with suboptimal catheter ablation (CA) outcomes. Thoracoscopic surgical ablation (SA) has shown promising efficacy in atrial fibrillation (AF). This multicentre randomized controlled trial tested whether SA was superior to CA as the first interventional strategy in de novo LSPAF. METHODS AND RESULTS: We randomized 120 LSPAF patients to SA or CA. All patients underwent predetermined lesion sets and implantable loop recorder insertion. Primary outcome was single procedure freedom from AF/atrial tachycardia (AT) ≥30 s without anti-arrhythmic drugs at 12 months. Secondary outcomes included clinical success (≥75% reduction in AF/AT burden); procedure-related serious adverse events; changes in patients' symptoms and quality-of-life scores; and cost-effectiveness. At 12 months, freedom from AF/AT was recorded in 26% (14/54) of patients in SA vs. 28% (17/60) in the CA group [OR 1.128, 95% CI (0.46-2.83), P = 0.83]. Reduction in AF/AT burden ≥75% was recorded in 67% (36/54) vs. 77% (46/60) [OR 1.13, 95% CI (0.67-4.08), P = 0.3] in SA and CA groups, respectively. Procedure-related serious adverse events within 30 days of intervention were reported in 15% (8/55) of patients in SA vs. 10% (6/60) in CA, P = 0.46. One death was reported after SA. Improvements in AF symptoms were greater following CA. Over 12 months, SA was more expensive and provided fewer quality-adjusted life-years (QALYs) compared with CA (0.78 vs. 0.85, P = 0.02). CONCLUSION: Single procedure thoracoscopic SA is not superior to CA in treating LSPAF. Catheter ablation provided greater improvements in symptoms and accrued significantly more QALYs during follow-up than SA. CLINICAL TRIAL REGISTRATION: ISRCTN18250790 and ClinicalTrials.gov: NCT02755688.

Journal article

Wu J-T, Zaman JAB, Yakupoglu HY, Vennela B, Emily C, Nabeela K, Jarman J, Haldar S, Jones DG, Wajid H, Shi R, Chen Z, Markides V, Wong Tet al., 2020, Catheter Ablation of Atrial Fibrillation in Patients With Functional Mitral Regurgitation and Left Ventricular Systolic Dysfunction, FRONTIERS IN CARDIOVASCULAR MEDICINE, Vol: 7, ISSN: 2297-055X

Journal article

Ghonim S, Ernst S, Keegan J, Giannakidis A, Spadotto V, Voges I, Smith G, Boutsikou M, Montanaro C, Wong T, Ho SY, McCarthy K, Shore D, Dimopoulos K, Uebing A, Swan L, Li W, Pennell D, Gatzoulis M, Babu-Narayan Set al., 2020, 3D late gadolinium enhancement cardiovascular magnetic resonance predicts inducibility of ventricular tachycardia in adults with repaired tetralogy of Fallot, Circulation: Arrhythmia and Electrophysiology, Vol: 13, Pages: 1331-1341, ISSN: 1941-3084

Background - Adults with repaired tetralogy of Fallot (rTOF) die prematurely from ventricular tachycardia (VT) and sudden cardiac death. Inducible VT predicts mortality. Ventricular scar, the key substrate for VT, can be non-invasively defined with late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) but whether this relates to inducible VT is unknown.Methods - Sixty-nine consecutive rTOF patients (43 male, mean 40{plus minus}15 years) clinically scheduled for invasive programmed VT-stimulation were prospectively recruited for prior 3D LGE CMR. Ventricular LGE was segmented and merged with reconstructed cardiac chambers and LGE volume measured.Results - VT was induced in 22(31%) patients. Univariable predictors of inducible VT included increased RV LGE (OR 1.15;p=0.001 per cm3), increased non-apical vent LV LGE (OR 1.09;p=0.008 per cm3), older age (OR 1.6;p=0.01 per decile), QRS duration ≥180ms (OR 3.5;p=0.02), history of non-sustained VT (OR 3.5; p=0.02) and previous clinical sustained VT (OR 12.8;p=0.003); only prior sustained VT (OR 8.02;p=0.02) remained independent in bivariable analyses after controlling for RV LGE volume (OR 1.14;p=0.003). An RV LGE volume of 25cm3 had 72% sensitivity and 81% specificity for predicting inducible VT (AUC 0.81;p<0.001). At the extreme cutoffs for 'ruling-out' and 'ruling-in' inducible VT, RV LGE >10cm3 was 100% sensitive and >36cm3 was 100% specific for predicting inducible VT.Conclusions - 3D LGE CMR-defined scar burden is independently associated with inducible VT and may help refine patient selection for programmed VT-stimulation when applied to an at least intermediate clinical risk cohort.

Journal article

Barracano R, Brida M, Guarguagli S, Palmieri R, Diller GP, Gatzoulis MA, Wong Tet al., 2020, Implantable cardiac electronic device therapy for patients with a systemic right ventricle, HEART, Vol: 106, Pages: 1052-1058, ISSN: 1355-6037

Journal article

Marinelli A, Behar JM, Colunga PM, Griffiths S, Gatzoulis MA, Wong Tet al., 2020, Intra-atrial block requiring dual-site atrial pacing through a femoral approach in a univentricular heart., HeartRhythm Case Rep, Vol: 6, Pages: 390-394, ISSN: 2214-0271

Journal article

Tilz RR, Fink T, Bartus K, Wong T, Vogler J, Nentwich K, Panniker S, Fang Q, Piorkowski C, Liosis S, Gaspar T, Sawan N, Metzner A, Nietlispach F, Maisano F, Lee RJ, Foran JP, Ouyang F, Sievert H, Deneke T, Kuck K-Het al., 2020, A collective European experience with left atrial appendage suture ligation using the LARIAT(+) device, EUROPACE, Vol: 22, Pages: 924-931, ISSN: 1099-5129

Journal article

Yang G, Chen J, Gao Z, Li S, Ni H, Angelini E, Wong T, Mohiaddin R, Nyktari E, Wage R, Xu L, Zhang Y, Du X, Zhang H, Firmin D, Keegan Jet al., 2020, Simultaneous left atrium anatomy and scar segmentations via deep learning in multiview information with attention, Future Generation Computer Systems: the international journal of grid computing: theory, methods and applications, Vol: 107, Pages: 215-228, ISSN: 0167-739X

Three-dimensional late gadolinium enhanced (LGE) cardiac MR (CMR) of left atrial scar in patients with atrial fibrillation (AF) has recently emerged as a promising technique to stratify patients, to guide ablation therapy and to predict treatment success. This requires a segmentation of the high intensity scar tissue and also a segmentation of the left atrium (LA) anatomy, the latter usually being derived from a separate bright-blood acquisition. Performing both segmentations automatically from a single 3D LGE CMR acquisition would eliminate the need for an additional acquisition and avoid subsequent registration issues. In this paper, we propose a joint segmentation method based on multiview two-task (MVTT) recursive attention model working directly on 3D LGE CMR images to segment the LA (and proximal pulmonary veins) and to delineate the scar on the same dataset. Using our MVTT recursive attention model, both the LA anatomy and scar can be segmented accurately (mean Dice score of 93% for the LA anatomy and 87% for the scar segmentations) and efficiently (0.27 s to simultaneously segment the LA anatomy and scars directly from the 3D LGE CMR dataset with 60–68 2D slices). Compared to conventional unsupervised learning and other state-of-the-art deep learning based methods, the proposed MVTT model achieved excellent results, leading to an automatic generation of a patient-specific anatomical model combined with scar segmentation for patients in AF.

Journal article

Shi R, Chen Z, Butcher C, Zaman JAB, Boyalla V, Wang YK, Riad O, Sathishkumar A, Norman M, Haldar S, Jones DG, Hussain W, Markides V, Wong Tet al., 2020, Diverse activation patterns during persistent atrial fibrillation by noncontact charge-density mapping of human atrium, JOURNAL OF ARRHYTHMIA, Vol: 36, Pages: 692-702, ISSN: 1880-4276

Journal article

Shi R, Parikh P, Chen Z, Angel N, Norman M, Hussain W, Butcher C, Haldar S, Jones DG, Riad O, Markides V, Wong Tet al., 2020, Validation of Dipole Density Mapping During Atrial Fibrillation and Sinus Rhythm in Human Left Atrium, JACC-CLINICAL ELECTROPHYSIOLOGY, Vol: 6, Pages: 171-181, ISSN: 2405-500X

Journal article

Li L, Wu F, Yang G, Xu L, Wong T, Mohiaddin R, Firmin D, Keegan J, Zhuang Xet al., 2020, Atrial scar quantification via multi-scale CNN in the graph-cuts framework, Medical Image Analysis, Vol: 60, ISSN: 1361-8415

Late gadolinium enhancement magnetic resonance imaging (LGE MRI) appears to be a promising alternative for scarassessment in patients with atrial fibrillation (AF). Automating the quantification and analysis of atrial scars can bechallenging due to the low image quality. In this work, we propose a fully automated method based on the graph-cutsframework, where the potentials of the graph are learned on a surface mesh of the left atrium (LA) using a multi-scaleconvolutional neural network (MS-CNN). For validation, we have included fifty-eight images with manual delineations.MS-CNN, which can efficiently incorporate both the local and global texture information of the images, has been shownto evidently improve the segmentation accuracy of the proposed graph-cuts based method. The segmentation could befurther improved when the contribution between the t-link and n-link weights of the graph is balanced. The proposedmethod achieves a mean accuracy of 0.856 ± 0.033 and mean Dice score of 0.702 ± 0.071 for LA scar quantification.Compared to the conventional methods, which are based on the manual delineation of LA for initialization, our methodis fully automatic and has demonstrated significantly better Dice score and accuracy (p < 0.01). The method is promisingand can be potentially useful in diagnosis and prognosis of AF.

Journal article

Karim N, Ho SY, Nicol E, Li W, Zemrak F, Markides V, Reddy V, Wong Tet al., 2020, The left atrial appendage in humans: structure, physiology, and pathogenesis, EUROPACE, Vol: 22, Pages: 5-18, ISSN: 1099-5129

Journal article

Butcher C, Sohaib S, Shun-Shin M, Haynes R, Khan H, Kyriacou A, Shi R, Cantor E, Chen Z, Panikker S, Haldar S, Cleland J, Wajid H, Markides V, Jones D, Lane RE, Whinnett ZI, Mason M, Francis D, Wong Tet al., 2019, High Precision Acute Haemodynamic Evaluation of Personalisation of Endocardial Left Ventricular Pacing Site in Patients With Heart Failure, Scientific Sessions of the American-Heart-Association, Publisher: LIPPINCOTT WILLIAMS & WILKINS, ISSN: 0009-7322

Conference paper

Li W, Yin Y, Dimopoulos K, Shimada E, Lascelles K, Griffiths S, Wong T, Gatzoulis M, Babu-Narayan Set al., 2019, Early and late effects of cardiac resynchronization therapy in adult congenital heart disease, Journal of the American Heart Association, Vol: 8, ISSN: 2047-9980

Background: There are limited data regarding cardiac resynchronization therapy (CRT) in adult congenital heart disease (ACHD). We aimed to assess early and late outcomes of CRT amongst patients with ACHD.Methods: We retrospectively studied ACHD patients receiving CRT (2004-2017). Clinical and echocardiographic data were analyzed at baseline, early (1.8±0.8 years) and late (4.7±0.8 years) follow-up after CRT.Results: Fifty-four ACHD patients (median age 46 years, range 18-73 years, 74% male) had CRT (biventricular paced >90%) and were followed for 5.7±3.0 years. Compared to baseline, CRT was associated with significant improvement at early follow-up in NYHA functional class, QRS duration and cardiothoracic ratio (P<0.05 for all); improvement in NYHA class was sustained at late follow-up.Amongst patients with a systemic left ventricle (LV; n=39), there was significant increase in LV ejection fraction (LVEF) and reduction in LV end-systolic volume at early and late follow up (P<0.05 for both). For patients with a systemic right ventricle (RV; n=15), there was a significant early but not late reduction in systemic RV basal and longitudinal diameters.Eleven patients died and 2 had heart transplantation unrelated to systemic ventricular morphology. Thirty-five (65%) patients responded positively to CRT but only baseline QRS duration was predictive of a positive response.Conclusions: CRT results in sustained improvement in functional class, systemic LV size and function. Patients with a systemic LV and prolonged QRS duration, independent of QRS morphology, were most likely to respond to CRT.

Journal article

Chen J, Zhang H, Zhang Y, Zhao S, Mohiaddin R, Wong T, Firmin D, Yang G, Keegan Jet al., 2019, Discriminative consistent domain generation for semi-supervised learning, International Conference on Medical Image Computing and Computer-Assisted Intervention, Publisher: Springer International Publishing, Pages: 595-604, ISSN: 0302-9743

Deep learning based task systems normally rely on a large amount of manually labeled training data, which is expensive to obtain and subject to operator variations. Moreover, it does not always hold that the manually labeled data and the unlabeled data are sitting in the same distribution. In this paper, we alleviate these problems by proposing a discriminative consistent domain generation (DCDG) approach to achieve a semi-supervised learning. The discriminative consistent domain is achieved by a double-sided domain adaptation. The double-sided domain adaptation aims to make a fusion of the feature spaces of labeled data and unlabeled data. In this way, we can fit the differences of various distributions between labeled data and unlabeled data. In order to keep the discriminativeness of generated consistent domain for the task learning, we apply an indirect learning for the double-sided domain adaptation. Based on the generated discriminative consistent domain, we can use the unlabeled data to learn the task model along with the labeled data via a consistent image generation. We demonstrate the performance of our proposed DCDG on the late gadolinium enhancement cardiac MRI (LGE-CMRI) images acquired from patients with atrial fibrillation in two clinical centers for the segmentation of the left atrium anatomy (LA) and proximal pulmonary veins (PVs). The experiments show that our semi-supervised approach achieves compelling segmentation results, which can prove the robustness of DCDG for the semi-supervised learning using the unlabeled data along with labeled data acquired from a single center or multicenter studies.

Conference paper

Whinnett Z, Sohaib SMA, Mason M, Duncan E, Tanner M, Lefroy D, Al-Obaidi M, Ellery S, Leyva-Leon F, Betts T, Dayer M, Foley P, Swinburn J, Thomas M, Khiani R, Wong T, Yousef Z, Rogers D, Kalra P, Dhileepan V, March K, Howard J, Kyriacou A, Mayet J, Kanagaratnam P, Frenneaux M, Hughes A, Francis Det al., 2019, Multicenter randomized controlled crossover trial comparing hemodynamic optimization against echocardiographic optimization of AV and VV delay of Cardiac Resynchronization Therapy: The BRAVO Trial, JACC: Cardiovascular Imaging, Vol: 12, Pages: 1407-1416, ISSN: 1936-878X

ObjectivesBRAVO (British Randomized Controlled Trial of AV and VV Optimization) is a multicenter, randomized, crossover, noninferiority trial comparing echocardiographic optimization of atrioventricular (AV) and interventricular delay with a noninvasive blood pressure method.BackgroundCardiac resynchronization therapy including AV delay optimization confers clinical benefit, but the optimization requires time and expertise to perform.MethodsThis study randomized patients to echocardiographic optimization or hemodynamic optimization using multiple-replicate beat-by-beat noninvasive blood pressure at baseline; after 6 months, participants were crossed over to the other optimization arm of the trial. The primary outcome was exercise capacity, quantified as peak exercise oxygen uptake. Secondary outcome measures were echocardiographic left ventricular (LV) remodeling, quality-of-life scores, and N-terminal pro–B-type natriuretic peptide.ResultsA total of 401 patients were enrolled, the median age was 69 years, 78% of patients were men, and the New York Heart Association functional class was II in 84% and III in 16%. The primary endpoint, peak oxygen uptake, met the criterion for noninferiority (pnoninferiority = 0.0001), with no significant difference between the hemodynamically optimized arm and echocardiographically optimized arm of the trial (mean difference 0.1 ml/kg/min). Secondary endpoints for noninferiority were also met for symptoms (mean difference in Minnesota score 1; pnoninferiority = 0.002) and hormonal changes (mean change in N-terminal pro–B-type natriuretic peptide -10 pg/ml; pnoninferiority = 0.002). There was no significant difference in LV size (mean change in LV systolic dimension 1 mm; pnoninferiority < 0.001; LV diastolic dimension 0 mm; pnoninferiority <0.001). In 30% of patients the AV delay identified as optimal was more than 20 ms from the nominal setting of 120 ms.ConclusionsOptimization of cardiac resynchronization therapy

Journal article

Willems S, Verma A, Betts TR, Murray S, Neuzil P, Ince H, Steven D, Sultan A, Heck PM, Hall MC, Tondo C, Pison L, Wong T, Boersma LV, Meyer C, Grace Aet al., 2019, Targeting Nonpulmonary Vein Sources in Persistent Atrial Fibrillation Identified by Noncontact Charge Density Mapping: UNCOVER AF Trial., Circ Arrhythm Electrophysiol, Vol: 12

Background Identification and elimination of nonpulmonary vein targets may improve clinical outcomes in patients with persistent atrial fibrillation (AF). We report on the use of a novel, noncontact imaging and mapping system that uses ultrasound to reconstruct atrial chamber anatomy and measures timing and density of dipolar, ionic activation (ie, charge density) across the myocardium to guide ablation of atrial arrhythmias. Methods The prospective, nonrandomized UNCOVER AF trial (Utilizing Novel Dipole Density Capabilities to Objectively Visualize the Etiology of Rhythms in Atrial Fibrillation) was conducted at 13 centers across Europe and Canada. Patients with persistent AF (>7 days, <1 year) aged 18 to 80 years, scheduled for de novo catheter ablation, were eligible. Before pulmonary vein isolation, AF was mapped and then iteratively remapped to guide each subsequent ablation of charge density-identified targets. AF recurrence was evaluated at 3, 6, 9, and 12 months using continuous 24-hour ECG monitors. The primary effectiveness outcome was freedom from AF >30 seconds at 12 months for a single procedure with a secondary outcome being acute procedural efficacy. The primary safety outcome was freedom from device/procedure-related major adverse events. Results Between October 2016 and April 2017, 129 patients were enrolled, and 127 underwent mapping and catheter ablation. Acute procedural efficacy was demonstrated in 125 patients (98%). At 12 months, single procedure freedom from AF on or off antiarrhythmic drugs was 72.5% (95% CI, 63.9%-80.3%). After 1 or 2 procedures, freedom from AF was 93.2% (95% CI, 87.1%-97.0%). A total of 29 (23%) retreatments because of arrhythmia recurrence were performed with average time from index procedure to first retreatment being 7 months. The primary safety outcome was 98% with no device-related major adverse events reported. Conclusions This novel ultrasound imaging and charge density mapping system safely guided ablatio

Journal article

Corden B, Jarman J, Whiffin N, Tayal U, Buchan R, Sehmi J, Harper A, Midwinter W, Lascelles K, Mason M, Baksi J, Pantazis A, Pennell D, Barton P, Prasad S, Wong T, Cook S, Ware Jet al., 2019, Association between titin truncating variants and life-threatening cardiac arrhythmias in patients with dilated cardiomyopathy and implantable defibrillator, JAMA Network Open, Vol: 2, Pages: 1-12, ISSN: 2574-3805

Importance There is a need for better arrhythmic risk stratification in nonischemic dilated cardiomyopathy (DCM). Titin-truncating variants (TTNtvs) in the TTN gene are the most common genetic cause of DCM and may be associated with higher risk of arrhythmias in patients with DCM.Objective To determine if TTNtv status is associated with the development of life-threatening ventricular arrhythmia and new persistent atrial fibrillation in patients with DCM and implanted cardioverter defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D) devices.Design, Setting, and Participants This retrospective, multicenter cohort study recruited 148 patients with or without TTNtvs who had nonischemic DCM and ICD or CRT-D devices from secondary and tertiary cardiology clinics in the United Kingdom from February 1, 2011, to June 30, 2016, with a median (interquartile range) follow-up of 4.2 (2.1-6.5) years. Exclusion criteria were ischemic cardiomyopathy, primary valve disease, congenital heart disease, or a known or likely pathogenic variant in the lamin A/C gene. Analyses were performed February 1, 2017, to May 31, 2017.Main Outcome and Measures The primary outcome was time to first device-treated ventricular tachycardia of more than 200 beats/min or first device-treated ventricular fibrillation. Secondary outcome measures included time to first development of persistent atrial fibrillation.Results Of 148 patients recruited, 117 adult patients with nonischemic DCM and an ICD or CRT-D device (mean [SD] age, 56.9 [12.5] years; 76 [65.0%] men; 106 patients [90.6%] with primary prevention indications) were included. Having a TTNtv was associated with a higher risk of receiving appropriate ICD therapy (shock or antitachycardia pacing) for ventricular tachycardia or fibrillation (hazard ratio [HR], 4.9; 95% CI, 2.2-10.7; P < .001). This association was independent of all covariates, including midwall fibrosis measured by late gadolinium enhanc

Journal article

Martin CA, Martin R, Maury P, Meyer C, Wong T, Dallet C, Shi R, Gajendragadkar P, Takigawa M, Frontera A, Cheniti G, Thompson N, Kitamura T, Vlachos K, Wolf M, Bourier F, Lam A, Duchâteau J, Massoullié G, Pambrun T, Denis A, Derval N, Dubois R, Hocini M, Haïssaguerre M, Jaïs P, Sacher Fet al., 2019, Effect of Activation Wavefront on Electrogram Characteristics During Ventricular Tachycardia Ablation., Circ Arrhythm Electrophysiol, Vol: 12

Background Catheter ablation of ventricular tachycardia (VT) in structural heart disease is challenging because of noninducibility or hemodynamic compromise. Ablation often depends on elimination of local abnormal ventricular activities (LAVAs) but which may be hidden in far-field signal. We investigated whether altering activation wavefront affects activation timing and LAVA characterization and allows a better understanding of isthmus anatomy. Methods Patients with ischemic cardiomyopathy underwent mapping using the ultra-high density Rhythmia system (Boston Scientific). Maps were generated for all stable VTs and with pacing from the atrium, right ventricular apex, and an left ventricular branch of the coronary sinus. Results Fifty-six paced maps and 23 VT circuits were mapped in 22 patients. In 79% of activation maps, there was ≥1 line of block in the paced conduction wavefront, with 93% having fixed block and 32% showing functional partial block. Bipolar scar was larger with atrial than right ventricular (31.7±18.5 versus 27.6±16.3 cm2, P=0.003) or left ventricular pacing (31.7±18.5 versus 27.0±19.2 cm2, P=0.009); LAVA areas were smaller with atrial than right ventricular (12.3±10.5 versus 18.4±11.0 cm2, P<0.001) or left ventricular pacing (12.3±10.5 versus 17.1±10.7 cm2, P<0.001). LAVA areas were larger with wavefront propagation perpendicular versus parallel to the line of block along isthmus boundaries (19.3±7.1 versus 13.6±7.4 cm2, P=0.01). All patients had successful VT isthmus ablation. In 11±8 months follow-up, 2 patients had a recurrence. Conclusions Wavefronts of conduction slowing/block may aid identification of critical isthmuses in unmappable VTs. Altering the activation wavefront leads to significant differences in conduction properties of myocardial tissue, along with scar and LAVA characterization. In patients where few LAVAs are identified during substrate mappi

Journal article

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