Professional background

Lead for cardiac arrhythmia services at UCLH, incorporating assessment of all types of heart rhythm problem, atrial fibrillation and AF ablation, blackouts and ectopic beats with weekly outpatient clinics. I also work at Barts Heart Centre, St. Bartholomew’s Hospital, one of the largest electrophysiology centres in Europe, where I perform catheter ablation for all types of arrhythmia, cardiac device implantation including conventional and leadless pacemakers, defibrillators, CRT devices, loop recorders and left atrial appendage occlusion devices.

I was appointed consultant Cardiologist & Electrophysiologist at The Heart Hospital, UCLH in 2008, moving to the Barts Heart Centre in 2015 when services were transferred. I lead the Left Atrial Appendage Occlusion Device programme at Barts and was education & training lead in Electrophysiology and Programme Director for Overseas Fellows for over 10 years.

After graduating from King’s College London in 1995, I trained in general cardiology at St. Bartholomew’s and The London Chest Hospitals before undertaking my doctorate (MD) research on mapping complex ventricular arrhythmias at The National Heart & Lung Institute, Imperial College, London. This work led to 1st prize in the Young Investigator Award competition for clinical research at the 2004 Heart Rhythm Society in San Francisco, USA. My specialist postgraduate training in electrophysiology & device implantation was at some of London’s largest arrhythmia centres at St. Mary’s Hospital, The Heart Hospital and St. George’s Hospital. In 2007 I completed a fellowship in pacing & electrophysiology at Prof. George Klein’s world-renowned electrophysiology unit in London, Ontario, Canada. I was made a Fellow of the Heart Rhythm Society and Royal College of Physicians in 2013. I am a member of the British Heart Rhythm Society and European Heart Rhythm Association. I sat on the British Heart Rhythm Society exam setting committee for >5 years and now sit on the European equivalent.

Research interests

I have research interests in many aspects of arrhythmia management, including atrial fibrillation, catheter ablation, myotonic dystrophy and its cardiac effects, and aspects of device implantation including left atrial appendage occlusion device implantation.

I have been Principal Investigator for multiple research studies. I was awarded a British Heart Foundation fellowship in 2001 to study ventricular arrhythmias using the then novel non-contact mapping technology.

As invited faculty, I have presented extensively at national and international conferences and have published over 60 peer-reviewed papers as well as a number of book chapters. I also have an interest in training & education of complex arrhythmias and for medicolegal aspects of cardiac arrhythmia.


Peer-reviewed papers

Waddingham P et al. Post-operative cardiac implantable electronic devices (CIEDs) in patients undergoing cardiac surgery: a contemporary experience. Europace (in press)

Papageorgiou N, Falconer D, Wyeth N, Lloyd G, Pellerin D, Speechly-Dick E, Segal OR, Lowe M, Rowland E, Lambiase PD, Chow AW, Bhattacharyya S. Effect of tricuspid regurgitation and right ventricular dysfunction on long-term mortality in patients undergoing cardiac devices implantation: >10-year follow-up study. Int J Cardiol 2020 May [online ahead of print]

Cobb V, Ezzat V, Higgins F, Lambiase P, Lowe M, Segal O, Chow AW. Chronic Performance of Riata 1580 and Endotak 0158 ICD Leads: A Single Centre Ten Year Experience. Pacing Clin Electrophysiol 2020 [online ahead of print]

Graham AJ, Orini M, Zacur E, Dhillon G, Daw H, Srinivasan NT, Martin C, Lane J, Mansell JS, Cambridge A, Garcia J, Pugliese F, Segal O, Ahsan S, Lowe M, Finlay M, Earley MJ, Chow A, Sporton S, Dhinoja M, Hunter RJ, Schilling RJ, Lambiase PD. Evaluation of ECG Imaging to Map Haemodynamically Stable and Unstable Ventricular Arrhythmias. Circ Arrhythm Electrophysiol 2020 [Epub ahead of print]

Papageorgiou N, Falconer D, Ioannou A, Wongwarawipat T, Barra S, Tousoulis D, Lim WY, Khan FZ, Ahsan S, Muthumala A, Hunter RJ, Finlay M, Creta A, Rowland E, Lowe M, Segal OR, Schilling RJ, Lambiase PD, Chow AW, Providencia R. Full blood count as potential predictor of outcomes in patients undergoing cardiac resynchronization therapy. Scientific Reports 2019;9:13016

Roberts PR, Pepper C, Rinaldi CA, Bates MGD, Thornley A, Somani R, Abozguia K, Harris S, Rao A, Pedersen M, McComb JM, Shepherd E, Moore P, Segal OR, Schilling RJ, Zaidi A. The use of a single chamber leadless pacemaker for the treatment of cardioinhibitory vasovagal syncope. Int J Cardiol Heart Vasc. 2019 Mar 28;23:100349 doi: 10.1016/j.ijcha.2019.100349. eCollection 2019 Jun.

Srinivasan NT, Orini M, Providencia R, Simon R, Lowe M, Segal OR, Chow AW, Schilling RJ, Hunter RJ, Taggart P, Lambiase PD. Differences in the upslope of the precordial body surface ECG T wave reflect right to left dispersion of repolarization in the intact human heart. Heart Rhythm 2019;16:943-51

Creta A, Chow AW, Sporton S, Finlay M, Papageorgiou N, Honarbakhsh S, Dhillon G, Graham A, Patel KH, Dhinoja M, Earley MJ, Hunter RJ, Lowe M, Rowland E, Segal OR, Calabrese V, Ricciardi D, Lambiase PD, Schilling RJ, Providência R. Procedural and quality assessment data on catheter ablation for fascicular ventricular tachycardia. Data Brief 2018;21:2376-2378

Creta A, Chow AW, Sporton S, Finlay M, Papageorgiou N, Honarbakhsh S, Dhillon G, Graham A, Patel KHK, Dhinoja M, Earley MJ, Hunter RJ, Lowe M, Rowland E, Segal OR, Calabrese V, Ricciardi D, Lambiase PD, Schilling RJ, Providência R. Catheter ablation for fascicular ventricular tachycardia: A systematic review. Int J Cardiol. 2019;276:136-148

Sawhney V, Volkova E, Shaukat M, Khan F, Segal O, Ahsan S, Chow A, Ezzat V, Finlay M, Lambiase P, Lowe M, Dhinoja M, Sporton S, Earley MJ, Hunter RJ, Schilling RJ. Impact of attributed audit on procedural performance in cardiac electrophysiology catheter laboratory. J Interv Card Electrophysiol 2019;56:199-203

Providencia R, Marijon E, Barra S, Reitan C, Breitenstein A, Defaye P, Papageorgiou N, Duehmke R, Winnik S, Ang R, Klug D, Gras D, Oezkartal T, Segal OR, Deharo JC, Leclercq C, Lambiase PD, Fauchier L, Bordachar P, Steffel J, Sadoul N, Piot O, Borgquist R, Agarwal S, Chow A, Boveda S; DAI-PP Investigators. Usefulness of a clinical risk score to predict the response to cardiac resynchronization therapy. Int J Cardiol 2018;1:260:82-87

Providencia R, Marijon E, Barra S, Papageorgiou N, Ioannou A, Lambiase P, Segal O, Chow A, Boveda S. Screen, EAARN, or valid-CRT score, which one best predicts CRT response and long-term survival? EP Europace 2017;19:i27

Providencia R, Teixeira C, Segal OR, Ullstein A, Mueser K, Lambiase PD. Empowerment of athletes with cardiac disorders: a new paradigm. Europace 2018;20:1243-51

Providencia R, Teixeira C, Segal OR, Ullstein A, Lambiase PD. Call for joint informed consent in athletes with inherited cardiac conditions. Open Heart. 2017;4:e000516

Providencia R, Craveiro Barra S, Papageorgiou N, Ioannou A, Rogers D, Wongwarawipat T, Falconer D, Duehmke R, Colicchia M, Babu GG, Segal O, Sporton S, Dhinoja M, Ahsan SY, Ezzat M. Dual-site Right Ventricular Pacing in Patients Undergoing Cardiac Resynchronization Therapy: Results of a Multicentre Propensity Matched Analysis. Pacing Clin Electrophysiol. 2017;40:1113-1120

Providencia R, Segal OR. Is it time to loosen the restrictions on athletes with cardiac disorders competing in sport? Br J Sports Medicine 2017;51:1056-57

Long-Term Results of Triventricular Versus Biventricular Pacing in Heart Failure: A Propensity-Matched Comparison. Providencia R, Rogers D, Papageorgiou N, Ioannou A, James A, Babu G, Cobb V, Ahsan S, Segal OR, Rowland E, Lowe M, Lambiase PD, Chow AWC. JACC Clin Electrophysiol. 2016;2:825-835

Honarbakhsh S, Providencia R, Srinivasan N, Ahsan S, Lowe M, Rowland E, Hunter RJ, Finlay M, Segal O, Earley MJ, Chow A, Schilling RJ, Lambiase PD. A propensity matched case-control study comparing efficacy, safety and costs of the subcutaneous vs. transvenous implantable cardioverter defibrillator. Int J Cardiol 2016;228:280-285

Papageorgiou N, Providência R, Srinivasan N, Bronis K, Moscoso Costa F, Cavaco D, Adragao P, Tousoulis D, Hunter R, Schilling R, Segal OR, Chow AW, Rowland E, Lowe M, Lambiase PD. Adenosine-guided pulmonary vein isolation versus conventional pulmonary vein isolation in patients undergoing atrial fibrillation ablation: an updated meta-analysis. Int J Cardiol 2016;227:151-160

Betts TR, Leo M, Panikker S, Kanagaratnam P, Koa-Wing M, Davies DW, Hildick-Smith D, Wynne DG, Ormerod O, Segal OR, Chow AW, Todd D, Cabrera Gomez S, Kirkwood GJ, Fox D, Pepper C, Foran J, Wong T. Percutaneous left atrial appendage occlusion using different technologies in the United Kingdom: A multicenter registry. Catheter Cardiovasc Interv. 2017;15:484-492

Providência R, Teixeira C, Segal OR, Ullstein A, Elliott P, Lambiase DP. A Call for Joint Informed Consent in Athletes with Inherited Cardiac Conditions. Open Heart 2017;4: e000516

Providência R, Boveda S, Defaye P, Segal O, Algalarrondo V, Sadoul N, Lambiase P, Piot O, Klug D, Perier MC, Bouzeman A, Barra S, Bories MC, Gras D, Fauchier L, Bordachar P, Babuty D, Deharo JC, Leclercq C, Marijon E, DAI-PP Investigators. Outcome of Primary Prevention Implantable Cardioverter Defibrillator Therapy According to New York Heart Association Functional Classification. AM J Cardiol 2016;118:1225-1232

Babu, GG, Webber M, Providência R, Kumar S, Gopalamurugan AB, Rogers D, Daw H, Ahsan S, Khan F, Chow A, Lowe M, Rowland E, Lambiase P, Segal OR. Ventricular Arrhythmia Burden in Patients with Heart Failure and Cardiac Resynchronization Devices - The Importance of Renal Function. J Cardiovasc Electrophysiol 2016;27:1328-1336

Srinivasan NT, Orini M, Simon RB, Providência R, Khan F, Segal OR, Babu G, Bradley R, Rowland E, Ahsan S, Chow AW, Lowe M, Taggart P, Lambiase P. Ventricular stimulus site influences dispersion of depolarization in the intact human heart. Am J Physiol Heart Circ Physiol 2016; 311:H545-54

Providencia R, Elliott P, Patel K, McCready J, Babu G, Srinivasan N, Bronis K, Papageorgiou N, Chow A, Rowland E, Lowe M, Segal OR, Lambiase PD. Catheter ablation for atrial fibrillation in hypertrophic cardiomyopathy: a systematic review and meta-analysis. Heart 2016; 102:1533-43

Providência R, Ganesha Babu G, Srinivasan NT, Bronis K, Lambiase PD, Segal OR. Is there still a role for CFAE ablation in addition to pulmonary vein isolation in patients with paroxysmal and persistent atrial fibrillation? A meta-analysis of 1,415 patients. Circ Arrhythm Electrophysiol 2015;8:1017-29

Ezzat VA, Lee VF, Ahsan S, Chow AW, Segal O, Rowland E, Lowe MD, Lambiase PD. A systematic review of ICD complications in randomised controlled trials versus registries: Is our “real-world” data an underestimation? Open Heart 2015;17: e000198

Gopalamurugan AB, Ganesha Babu A, Rogers, DP, Simpson AL, Ahsan Y, Lambiase PD, Chow AW, Lowe MD, Rowland E, Segal OR. Is CRT pro-arrhythmic? A comparative analysis of the occurrence of ventricular arrhythmias between patients implanted with CRTs and ICDs. Frontiers in Physiology (Cardiac Electrophysiology Section) 2014;5:334

Finlay MC, Ahmed AK, Sugrue A, Bhar-Amato J, Quarta G, Pantazis A, Ciaccio EJ, Syrris P, Sen-Chowdhry S, Ben-Simon R, Chow AW, Lowe MD, Segal OR, McKenna WJ, Lambiase PD. Dynamic Conduction and Repolarisation Changes in Early Arrhythmogenic Right Ventricular Cardiomyopathy versus Benign Outflow Tract Ectopy Demonstrated by High Density Mapping & Paced Surface ECG Analysis. PLoS One 2014;9:e99125

McCready J, Chow AW, Lowe MD, Segal OR, Ahsan S, de Bono J, Dhaliwal M, Mfuko C, Ng A, Rowland ER, Bradley RJ, Paisey J, Roberts P, Morgan JM, Sandilands A, Yue A, Lambiase PD. Safety and efficacy of multipolar pulmonary vein ablation catheter vs. irrigated radiofrequency ablation for paroxysmal atrial fibrillation: a randomized multicentre trial. Europace 2014;16:1145-53

Ahsan SY, Saberwal B, Lambiase PD, Chaubey S, Segal OR, Gopalamurugan AB, McCready J, Rogers DP, Lowe MD, Chow AWC. An 8-year single-centre experience of cardiac resynchronisation therapy: procedural success, early and late complications, and left ventricular lead performance. Europace 2013;15:711-7

Ezzat VA, Chew A, McCready JW, Lambiase PD, Chow AW, Lowe MD, Rowland E, Segal OR. Catheter Ablation of Atrial Fibrillation – Patient Satisfaction from a Single Center UK Experience. J Interv Card Electrophysiol 2013;37:291-303

Wadhera V, Buxton AE, Antoniadis AP, McCready JW, Redpath CJ, Segal OR, Rowland E, Lowe MD, Lambiase PD, Chow AW. The use of a novel nitinol guidewire to facilitate transseptal puncture and left atrial catheterization for catheter ablation procedures. Europace 2011;13:1401-5

Veasey RA, Segal OR, Large J, Hyde J, Sulke AN. The efficacy of intraoperative atrial radiofrequency ablation for atrial fibrillation during concomitant cardiac surgery – The Surgical Atrial Fibrillation Suppression (SAFS) Study. J Interv Card Electrophysiol 2011;32:29-35

Jones DG, McCready JW, Kaba RA, Ahsan SY, Lyne JC, Wang J, Segal OR, Markides V, Lambiase PD, Wong T, Chow AW. A multi-purpose spiral high density mapping catheter: initial clinical experience in complex atrial arrhythmias. J Interv Card Electrophysiol 2011;31:225-35

Gula LJ, Massel D, Leong-Sit P, Gray C, Fox D, Segal OR, Krahn AD, Yee R, Klein GJ, Skanes AC. Does Adenosine response predict clinical recurrence of atrial fibrillation after pulmonary vein isolation? J Cardiovasc Electrophysiol 2011;22:982-6

McCready JW, Smedley T, Lambiase PD, Ahsan SY, Segal OR, Rowland E, Lowe MD, Chow AW. Predictors of recurrence following radiofrequency ablation for persistent atrial fibrillation. Europace 2011;13:355-61

McCready JW, Nunn L, Lambiase PD, Ahsan S, Segal OR, Rowland E, Lowe MD, Chow AW. Incidence of left atrial thrombus prior to atrial fibrillation ablation. Is pre-procedural transoesophageal echocardiography mandatory? Europace 2010;12:927-932

Segal OR, Chow AW, Peters NS, Davies DW. Mechanisms that initiate ventricular tachycardia in the infarcted human heart. Heart Rhythm 2010;7:57-64

Segal OR, Gula LJ, Skanes AC, Krahn AD, Yee R, Klein GJ. Differential ventricular entrainment – a maneuver to differentiate AV node reentrant tachycardia from orthodromic reciprocating tachycardia. Heart Rhythm 2009;6:493-500

Ciaccio EJ, Chow AW, Kaba RA, Davies DW, Segal OR, Peters NS. Detection of the Diastolic Pathway, Circuit Morphology and Inducibility of Human Post-Infarction Ventricular Tachycardia from Mapping in Sinus Rhythm. Heart Rhythm 2008;5:981-991

Segal OR, Wong T, Chow AW, Jarman J, Schilling RJ, Markides V, Peters NS, Davies DW. Intra-coronary guidewire mapping – A novel technique to guide ablation of human ventricular tachycardia. J Interv Card Electrophysiol 2007;18:143-154

Segal OR, Chow AW, Markides V, Davies DW, Peters NS. Characterisation of the effects of single ventricular extrastimuli on endocardial activation in human, infarct-related ventricular tachycardia. J Am Coll Cardiol 2007;49:1315-1323

Segal OR, Chow AW, Wong T, Trevisi N, Lowe MD, Davies DW, Della Bella P, Packer DL, Peters NS. A novel algorithm for determining endocardial VT exit site from 12 lead surface ECG characteristics in human, infarct-related ventricular tachycardia. J Cardiovasc Electrophysiol 2007;18:161-168

Kojodjojo P, Kanagaratnam P, Segal OR, Hussain W, Nicholas S Peters. The effects of carbenoxolone on human myocardial conduction: a tool to investigate the role of gap-junctional uncoupling in human arrhythmogenesis. J Am Coll Cardiol. 2006:19;48:1242-9

Segal OR, Chow AWC, Markides V, Schilling RJ, Peters NS, Davies DW. Long-term results after ablation of infarct-related ventricular tachycardia. Heart Rhythm 2005;2:474-482

Chow AWC, Segal OR, Davies DW, Peters NS. Mechanism of pacing induced ventricular fibrillation in the infarcted human heart. Circulation 2004;110:1725-1730

Segal OR, Dawson JR, Gupta S. The use of echocardiography for stroke and peripheral embolus: Is it time for British/European guidelines? Br J Cardiol 2002;9:287-290


Antoniou S, Arden C, Beyer-Westendorf J, Hargroves D, McCormack T, McInnes G, Patel R, Segal OR. Unlocking the potential of NOACs. Br J Cardiol 2014;21(suppl 2):S1–S7

Segal OR. Rate control for atrial fibrillation – one drug or two? PMJ 2009; 85(1004):281-2

Prize Essays

Segal O “Physician - govern thyself?” J R Coll Physicians Lond 2000;34:492-3

Case reports

Mann I, Segal OR. A case of durata ICD lead coil externalisation - inside-out lead abrasion? HeartRhythm Case Reports 2016;2:283-85

Srinivasan N, Segal OR. Biventricular pacing and coronary sinus ICD lead implantation in a patient with a mechanical tricuspid valve replacement. J Cardiol Cases 2015;12:180-2

Zorzi A, Sepahpour A, Tomé-Esteban MT, Lambiase PD, Segal OR. An unusual case of pre-excitation treated with a pacemaker PACE 2015;38:282-5

Novak J, Sepahpour A, Segal OR. Repetitive narrow and broad beats causing mild LV impairment. What is the mechanism? PACE 2014;37:1565-7

Novak J, Segal OR. Acute respiratory distress syndrome following straightforward pulmonary vein isolation. Europace 2014;16:490

Opel A, Segal OR, Chow A, Ward DE. A broad complex tachycardia: What is the mechanism? Heart Rhythm 2011;8:1985-7

Ahsan SY, Flett AS, Lamiase PD, Segal OR. First report of phrenic nerve injury during pulmonary vein isolation using the Ablation Frontiers pulmonary vein ablation catheter. J Interv Card Electrophysiol. 2010;29:187-90

Segal OR, Chow AW, Lambiase PD. Narrow and broad QRS complexes – what is the mechanism? Heart Rhythm 2010;7:565-6

Gofton TE, Segal OR, Skanes AC Fraser AJ, Hyson C. Lateral medullary syndrome presenting with ataxia and bradycardia. Can J Neurol Sci 2009;36:390-2

Grimster A, Segal OR, Behr E. Type I Brugada ECG pattern during recovery phase of exercise testing. Europace 2008;10:897-898

Segal OR, Ward DE. Is there a connection? J Cardiovasc Electrophysiol 2008;19:879-881

Segal OR, Leong-Sit P, Skanes AC, Gula LJ, Krahn AD, Yee R, Klein GJ. A sheep in wolf’s clothing? J Cardiovasc Electrophysiol 2007;18:1338-9

Leong-Sit P, Segal OR, Skanes AC, Gula LJ, Krahn AD, Yee R, Klein GJ. A case of preexcitation? J Cardiovasc Electrophysiol 2007;18:998-999

Lindsay AC, Wong T, Segal O, Peters NS. An unusual twist: ventricular tachycardia induced by a loop in a right ventricular pacing wire. QJM 2006;99:347-8

Wong T, Segal OR, Markides V, Davies DW, Peters NS. Cryoablation of Focal Atrial Tachycardia Originating Close to the Atrioventricular Node. J Cardiovasc Electrophysiol 2004;15:838

Segal OR, Markides V, Kanagaratnam P, Wong T, Peters NS. Multiple distinct right atrial endocardial origins in a patient with atrial tachycardia. Mapping and ablation using non-contact mapping. PACE 2004; 27:541-544

Segal OR, Markides V, Wong T, Peters NS. Too focused? The perils of a fashionable diagnosis. J Cardiovasc Electrophysiol 2002;13:1058-60

Segal OR, Fox K. Successful pregnancy following a peripartum cardiomyopathy Br J Cardiol 2002;9:50-52

Segal OR, Gibbs JSR, Sheppard MN. Eosinophilic aortitis and valvitis requiring aortic valve replacement. Heart 2001;86:245

Segal OR, Baker CSR, Banim S. Percutaneous coronary intervention with adjunctive abciximab and clopidogrel in a patient with idiopathic thrombocytopaenic purpura. Int J Cardiovasc Intervent 2001;4:35-38

Segal OR, Robinson NM, Timmis AD. Recurrent myxoma of the right ventricle. Heart 2000;84:652

Williams A, Segal O, Andrews B. Short gastric artery perforation after use of 'ecstasy'. J R Soc Med 1998;91:541-542

Book Chapters

Opel A, Segal OR. “Cardiac pacing and implantable cardioverter/defibrillators” in Oh’s Intensive Care Manual (8th Edition), (Eds.) A Bersten & N Soni. Butterworth, Heinemann, Elsevier 2019

Opel A, Segal OR. “Cardiac pacing and implantable cardioverter/defibrillators” in Oh’s Intensive Care Manual (7th Edition), (Eds.) A Bersten & N Soni. Butterworth, Heinemann, Elsevier 2014

Segal OR, Linton NF, Malcolme-Lawes L, Davies DW. “Three-Dimenisonal Cardiac Mapping Techniques in Catheter Ablation” in Electrophysiological Disorders of the Heart, Chapter 92, 1319-1328. (Eds.) Saksena S and Camm AJ. Elsevier Saunders, Philadelphia, USA, 2012

Segal OR, Koa-Wing M, Jarman J, Peters NS, Markides V, Davies DW. “Intracardiac Mapping” in Comprehensive Electrocardiology (2nd Edition), (Eds.) Camm AJC & MacFarlane PW. Springer 2010

Segal OR, Markides V, Davies DW, Peters NS. “Temporary cardiac pacing” in Cardiac Pacemakers and Defibrillation: All you wanted to know (1st Edition), (Eds.) Chow AWC & Buxton AE. Blackwell 2006

Markides V, Segal OR, Tondato F, Peters NS. “Mapping” in Cardiac Electrophysiology: From Cell to Bedside (4th Edition), (Eds.) Zipes DP & Jalife J. WB Saunders 2004