Imperial College London

DrViasMarkides

Faculty of MedicineNational Heart & Lung Institute

Honorary Clinical Senior Lecturer
 
 
 
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Contact

 

+44 (0)20 7351 8619v.markides

 
 
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Assistant

 

Dr Tom Wong +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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165 results found

Adasuriya G, Barsky A, Kralj-Hans I, Mohan S, Gill S, Chen Z, Jarman J, Jones D, Valli H, Gkoutos GV, Markides V, Hussain W, Wong T, Kotecha D, Haldar Set al., 2024, Remote monitoring of atrial fibrillation recurrence using mHealth technology (REMOTE-AF), European Heart Journal - Digital Health

<jats:title>Abstract</jats:title> <jats:sec> <jats:title>Aims</jats:title> <jats:p>This proof-of-concept study sought to evaluate changes in heart rate (HR) obtained from a consumer wearable device and compare against implantable loop recorder (ILR)-detected recurrence of atrial fibrillation (AF) and atrial tachycardia (AT) after AF ablation.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods and results</jats:title> <jats:p>REMOTE-AF (NCT05037136) was a prospectively designed sub-study of the CASA-AF randomized controlled trial (NCT04280042). Participants without a permanent pacemaker had an ILR implanted at their index ablation procedure for longstanding persistent AF. Heart rate and step count were continuously monitored using photoplethysmography (PPG) from a commercially available wrist-worn wearable. Photoplethysmography-recorded HR data were pre-processed with noise filtration and episodes at 1-min interval over 30 min of HR elevations (Z-score = 2) were compared with corresponding ILR data. Thirty-five patients were enrolled, with mean age 70.3 ± 6.8 years and median follow-up 10 months (interquartile range 8–12 months). Implantable loop recorder analysis revealed 17 out of 35 patients (49%) had recurrence of AF/AT. Compared with ILR recurrence, wearable-derived elevations in HR ≥ 110 beats per minute had a sensitivity of 95.3%, specificity 54.1%, positive predictive value (PPV) 15.8%, negative predictive value (NPV) 99.2%, and overall accuracy 57.4%. With PPG-recorded HR elevation spikes (non-exercise related), the sensitivity was 87.5%, specificity 62.2%, PPV 39.2%, NPV 92.3%, and overall accuracy 64.0% in the entire patient cohort. In the AF/AT recurrence only group, sensitivity was 87.6%, specificity 68.3%, PPV 53.6%, NPV 93.0%, and overall accuracy 75.0%.<

Journal article

O'Connor M, Barbero U, Kramer DB, Lee A, Hua A, Ismail T, Mccarthy KP, Niederer S, Rinaldi CA, Markides V, Clarke J-RD, Babu-Narayan S, Ho SY, Wong Tet al., 2023, Anatomic, histologic, and mechanical features of the right atrium: implications for leadless atrial pacemaker implantation, EUROPACE, Vol: 25, ISSN: 1099-5129

Journal article

Khan HR, Yakupoglu HY, Kralj-Hans I, Haldar S, Bahrami T, Clague J, De Souza A, Hussain W, Jarman J, Jones DG, Salukhe T, Markides V, Gupta D, Khattar R, Wong T, CASA AFIet al., 2023, Left Atrial Function Predicts Atrial Arrhythmia Recurrence Following Ablation of Long-Standing Persistent Atrial Fibrillation, CIRCULATION-CARDIOVASCULAR IMAGING, Vol: 16, ISSN: 1941-9651

Journal article

Butcher CJT, Cantor E, Sohaib A, Shun-Shin MJ, Haynes R, Khan H, Kyriacou A, Shi R, Chen Z, Haldar S, Cleland JGF, Hussain W, Markides V, Jones DG, Lane RE, Mason MJ, Whinnett ZI, Francis DP, Wong Tet al., 2023, Variation in optimal hemodynamic atrio-ventricular delay of biventricular pacing with different endocardial left ventricular lead locations using precision hemodynamics, JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Vol: 34, Pages: 1431-1440, ISSN: 1045-3873

Journal article

O'Connor M, Riad O, Shi R, Hunnybun D, Li W, Jarman JWE, Foran J, Rinaldi CA, Markides V, Gatzoulis MA, Wong Tet al., 2023, Left bundle branch area pacing in congenital heart disease, EUROPACE, Vol: 25, Pages: 561-570, ISSN: 1099-5129

Journal article

O'Connor M, Shi R, Kramer DB, Riad O, Hunnybun D, Jarman JWE, Foran J, Cantor E, Markides V, Wong Tet al., 2023, Conduction system pacing learning curve: Left bundle pacing compared to His bundle pacing, IJC HEART & VASCULATURE, Vol: 44

Journal article

Zakeri R, Ahluwalia N, Tindale A, Omar F, Packer M, Khan H, Baker V, Honarbakhsh S, Earley MJ, Sporton S, Schilling RJ, Jones D, Markides V, Hunter RJ, Wong Tet al., 2023, Long-term outcomes following catheter ablation versus medical therapy in patients with persistent atrial fibrillation and heart failure with reduced ejection fraction, EUROPEAN JOURNAL OF HEART FAILURE, Vol: 25, Pages: 77-86, ISSN: 1388-9842

Journal article

Malaczynska-Rajpold K, Jarman J, Shi R, Wright P, Wong T, Markides Vet al., 2022, Beyond pulmonary vein isolation for persistent atrial fibrillation: sequential high-resolution mapping to guide ablation, JOURNAL OF INTERVENTIONAL CARDIAC ELECTROPHYSIOLOGY, Vol: 65, Pages: 53-62, ISSN: 1383-875X

Journal article

Nashat H, Habibi H, Heng EL, Nicholson C, Gledhill JR, Obika BD, Yassaee AA, Markides V, McCleery P, Gatzoulis MAet al., 2022, Patient monitoring and education over a tailored digital application platform for congenital heart disease: A feasibility pilot study., Int J Cardiol, Vol: 362, Pages: 68-73

BACKGROUND: Patients with adult congenital heart disease (ACHD) are a rapidly growing cardiovascular population with increasing health needs and co-morbidities. Furthermore, their management requires frequent and ongoing hospital visits which can be burdensome. Digital health and remote monitoring have been shown to have a vast potential to enhance delivery of healthcare for patients, reducing their need for travel to clinic appointments therefore reducing costs to the patient and the healthcare service. METHODS: Patients over the age of 16 with a diagnosis of ACHD were invited to use the tailored digital application too. They were monitored for a period of 6 months. Information on patient demographics, time using the application, flagged events that prompted clinical reviews and their feedback through patient surveys were collected. RESULTS: A total of 103 patients were enrolled and registered to use the digital application tool. There were 57 (56%) males, median age at the time of enrolment was 39 (16-73) years. The majority (96%) had a moderate or complex ACHD according to the ACC/AHA classification. There was a total of 7 modules that were completed on a weekly basis. The median length of a participant session was 2.2 min and the mean time to complete a module was 21 s. In total, 35 (67%) felt that the application helped them better manage their cardiac condition. Almost all (94%) of patients expressed that they would like to continue using the application beyond the pilot. There were 18 flagged events during the 6 month observation period, and 50% of received early clinical intervention. CONCLUSION: Application based remote monitoring in this select group was well received and potentially holds large benefit to patients both clinically and economically. There were no safety concerns in our pilot feasibility study. Our data may inform much needed and timely investment in digital health.

Journal article

Sarkozy A, Vijgen J, De Potter T, Schilling R, Markides Vet al., 2022, An early multicenter experience of the novel high-density star-shaped mapping catheter in complex arrhythmias, JOURNAL OF INTERVENTIONAL CARDIAC ELECTROPHYSIOLOGY, Vol: 64, Pages: 223-232, ISSN: 1383-875X

Journal article

Griffiths S, Behar JM, Kramer DB, Debney MT, Monkhouse C, Lefas AY, Lowe M, Amin F, Cantor E, Boyalla V, Karim N, Till J, Markides V, Clague JR, Wong Tet al., 2022, The long-term outcomes of cardiac implantable electronic devices implanted via the femoral route, Pacing and Clinical Electrophysiology, Vol: 45, Pages: 481-490, ISSN: 0147-8389

BACKGROUND: Conventional superior access for cardiac implantable electronic devices (CIEDs) is not always possible and femoral CIEDs (F-CIED) are an alternative option when leadless systems are not suitable. The long-term outcomes and extraction experiences with F-CIEDs, in particular complex F-CIED (ICD/CRT devices), remain poorly understood. METHODS: Patients referred for F-CIEDs implantation between 2002 and 2019 at two tertiary centers were included. Early complications were defined as ≤30 days following implant and late complications >30 days. RESULTS: Thirty-one patients (66% male; age 56 ± 20 years; 35% [11] patients with congenital heart disease) were implanted with F-CIEDs (10 ICD/CRT and 21 pacemakers). Early complications were observed in 6.5% of patients: two lead displacements. Late complications at 6.8 ± 4.4 years occurred in 29.0% of patients. This was higher with complex F-CIED compared to simple F-CIED (60.0% vs. 14.3%, p = .02). Late complications were predominantly generator site related (n = 8, 25.8%) including seven infections/erosions and one generator migration. Eight femoral generators and 14 leads (median duration in situ seven [range 6-11] years) were extracted without complication. CONCLUSIONS: Procedural success with F-CIEDs is high with clinically acceptable early complication rates. There is a notable risk of late complications, particularly involving the generator site of complex devices following repeat femoral procedures. Extraction of chronic F-CIED in experienced centers is feasible and safe.

Journal article

Shi R, Zaman JAB, Chen Z, Shi X, Zhu M, Sathishkumar A, Boyalla V, Karim N, Cantor E, Haldar S, Jones DG, Hussain W, Markides V, Virdee M, Wang X, Grace A, Wong Tet al., 2022, Novel aggregated multiposition noncontact mapping of atrial tachycardia in humans: From computational modeling to clinical validation, HEART RHYTHM, Vol: 19, Pages: 61-69, ISSN: 1547-5271

Journal article

Haldar S, Khan HR, Boyalla V, Kralj-Hans I, Jones S, Lord J, Onyimadu O, Sathishkumar A, Bahrami T, Clague J, De Souza A, Francis D, Hussain W, Jarman J, Jones DG, Chen Z, Mediratta N, Hyde J, Lewis M, Mohiaddin R, Salukhe T, Murphy C, Kelly J, Khattar R, Toff WD, Markides V, McCready J, Gupta D, Wong Tet al., 2021, Thoracoscopic surgical ablation versus catheter ablation as first-line treatment for long-standing persistent atrial fibrillation: the CASA-AF RCT, Efficacy and Mechanism Evaluation, Vol: 8, Pages: 1-122, ISSN: 2050-4365

<jats:sec id="abs1-1"> <jats:title>Background</jats:title> <jats:p>Standalone thoracoscopic surgical ablation may be more effective than catheter ablation in patients with long-standing persistent atrial fibrillation.</jats:p> </jats:sec> <jats:sec id="abs1-2"> <jats:title>Objectives</jats:title> <jats:p>To determine whether or not surgical ablation is clinically superior to catheter ablation as the first-line treatment strategy in long-standing persistent atrial fibrillation.</jats:p> </jats:sec> <jats:sec id="abs1-3"> <jats:title>Design</jats:title> <jats:p>This was a prospective, multicentre, randomised control trial.</jats:p> </jats:sec> <jats:sec id="abs1-4"> <jats:title>Setting</jats:title> <jats:p>Four NHS tertiary centres in England.</jats:p> </jats:sec> <jats:sec id="abs1-5"> <jats:title>Participants</jats:title> <jats:p>Adults with long-standing persistent atrial fibrillation, who had European Heart Rhythm Association symptom scores &gt; 2 and who were naive to previous catheter ablation or thoracic/cardiac surgery.</jats:p> </jats:sec> <jats:sec id="abs1-6"> <jats:title>Interventions</jats:title> <jats:p>Minimally invasive thoracoscopic surgical ablation and conventional catheter ablation (control intervention).</jats:p> </jats:sec> <jats:sec id="abs1-7"> <jats:title>Mai

Journal article

Obika BD, Dolezova N, Ponzo S, Valentine S, Shah S, Gledhill J, Plans D, Nicholson C, Walters C, Stephen L, Ng S, Ayres J, Petrou M, Bhudia S, Denny C, Schrauwers H, Markides Vet al., 2021, Implementation of a mHealth solution to remotely monitor patients on a cardiac surgical waiting list: service evaluation, JAMIA OPEN, Vol: 4

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

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

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

Gue YX, Kanji R, Markides V, Gorog DAet al., 2020, Angiotensin Converting Enzyme 2 May Mediate Disease Severity In COVID-19, AMERICAN JOURNAL OF CARDIOLOGY, Vol: 130, Pages: 161-162, ISSN: 0002-9149

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

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

Gue YX, Spinthakis N, Markides V, Wong T, Gorog Det al., 2019, Patients with atrial fibrillation exhibit a systemic prothrombotic state attributable to impaired endogenous fibrinolysis, Congress of the European-Society-of-Cardiology (ESC) / World Congress of Cardiology, Publisher: OXFORD UNIV PRESS, Pages: 2948-2948, ISSN: 0195-668X

Conference paper

Shi R, Pope MTB, Boyalla V, Jones DG, Haldar S, Hussain W, Markides V, Betts TR, Wong Tet al., 2019, Core to block: a new ablation strategy for treating persistent atrial fibrillation, Congress of the European-Society-of-Cardiology (ESC) / World Congress of Cardiology, Publisher: OXFORD UNIV PRESS, Pages: 573-573, ISSN: 0195-668X

Conference paper

Karim N, Marinelli A, Cantor E, Boyalla V, Malaczynska-Rajpold K, Ahmed O, Khan H, Haldar S, Jones D, Hussein W, Markides V, Wong T, Jarman Jet al., 2019, Safety of atrial fibrillation catheter ablation in the elderly, Congress of the European-Society-of-Cardiology (ESC) / World Congress of Cardiology, Publisher: OXFORD UNIV PRESS, Pages: 1775-1775, ISSN: 0195-668X

Conference paper

Shi R, Chen Z, Butcher C, Zaman Z, Boyalla V, Wang YK, Riad O, Sathishkumar A, Norman M, Haldar S, Jones DG, Hussain W, Markides V, Wong Tet al., 2019, Diverse activation patterns during persistent atrial fibrillation characterised by dipole density non-contact mapping, Congress of the European-Society-of-Cardiology (ESC) / World Congress of Cardiology, Publisher: OXFORD UNIV PRESS, Pages: 2354-2354, ISSN: 0195-668X

Conference paper

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

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