About Dr Segal

London Cardiologist and Electrophysiologist

Dr Oliver Segal


Consultant Cardiologist

London Atrial Fibrillation London

Dr Oliver Segal has over 15 years’ experience in the management of arrhythmias, performing catheter ablation for atrial fibrillation and other arrhythmias, as well as implanting pacemakers, defibrillators and other cardiac devices. Dr Segal specialises in electrophysiology – the study of heart rhythm disorders.

He focuses on seeing patients with rapid palpitations and tachycardias, irregular heartbeats, ectopic or ‘skipped’ beats, pauses and slow heartbeats, dizzy spells and blackouts, including patients with breathlessness and tiredness due to atrial fibrillation (AF). He is an expert in performing electrophysiology studies, catheter ablation for all types of arrhythmia and implanting pacemakers, defibrillators (ICDs), loop recorders and biventricular pacing systems.

He has performed over 1900 electrophysiology studies and ablations (including the use of three-dimensional and non-contact mapping systems) and over 1000 device implantation procedures. He also performs pacemaker lead extraction and implants left atrial appendage occlusion devices (the Watchman and Amulet devices) for patients with AF and high risk of stroke who cannot take anticoagulants or when anticoagulants have failed.

London Cardiologist Dr Oliver Segal sees patients privately at The Harley Street Clinic.


‘Overwhelmingly positive. I felt that the advice given was practical and pragmatic. Oliver appears to give the unvarnished truth and is extremely helpful in presenting the options and evaluating the possible outcomes. The follow up is concise and thorough. I would unhesitatingly recommend him’

Clinical and research endeavours

Dr Segal’s clinical and research endeavours centre around atrial fibrillation ablation, mapping ventricular arrhythmias and diagnostics for SVT. He also has specialist interests in conduction disease in patients with myotonic dystrophy and the development of scoring systems to identify risk factors to guide cardiac device implantation in different patient groups. He presents and publishes widely on key aspects of cardiac arrhythmias and device implantation both nationally and internationally.

Education and Training

Dr Segal graduated from King’s College London and King’s College Hospital, London in 1995. He trained in general cardiology at St Bartholomew’s and The London Chest Hospitals. His specialist postgraduate training in cardiology and electrophysiology and device implantation was undertaken at St Mary’s Hospital, The Heart Hospital (UCLH) and St George’s Hospital in London. In 2007 he completed a fellowship in pacing and electrophysiology at Prof George Klein’s world-renowned electrophysiology unit in London, Ontario, Canada.

During his training, Dr Segal undertook a period of research on mapping complex ventricular arrhythmias at The National Heart and Lung Institute, Imperial College, London and was awarded his doctorate (MD) for this work in 2008. He presented part of that research at the 2004 Heart Rhythm Society in San Francisco, USA where he won first prize in the highly prestigious Young Investigator Award competition for clinical research.

Consultant appointments

Dr Segal was appointed as a Consultant Cardiologist in London, in the ‘NHS at The Heart Hospital’ (University College London Hospitals, 2008) moving to the Barts Heart Centre, St Bartholomew’s Hospital in April 2015 when services were transferred. He is Lead for Education and Training in Electrophysiology and Programme Director for Overseas Fellows as well as lead for the Left Atrial Appendage Occlusion Device programme. He is also Lead for Arrhythmia and Electrophysiology at University College Hospital and runs weekly arrhythmia clinics.

He sees patients privately at The Harley Street Clinic. He was made a Fellow of the Heart Rhythm Society and Royal College of Physicians in 2013.

More information

Editorials and Prize Essays


  • 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

Journal Publications

Dr Segal has published extensively. His publications include:

Peer reviewed papers:

  • 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. PACE 2017 (in press)
  • Providencia R, Segal OR. Is it time to loosen the restrictions on athletes with cardiac disorders competing in sport? Br J Sports Medicine 2017 (in press)
  • 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. 2016 (in press)
  • 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 2016 (in press)
  • Providência R, Boveda S, Defaye P, Segal OR, 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
  • Ganesha Babu, G, 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 (in press)
  • 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 (in press)
  • Providência 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 (in press)
  • Providência R, Lambiase PD, Srinivasan N, Ganesh Babu G, Bronis K, Ahsan S, Khan FZ, Chow AW, Rowland E, Lowe M, Segal OR. Is There Still a Role for Complex Fractionated Atrial Electrogram Ablation in Addition to Pulmonary Vein Isolation in Patients With Paroxysmal and Persistent Atrial Fibrillation? Meta-Analysis of 1415 Patients. Circ Arrhythm Electrophysiol. 2015 Oct;8(5):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 AWCAn 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 maaping 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

Case Reports

  • Mann I, Segal OR. A case of durata ICD lead coil externalisation – inside-out lead abrasion? HeartRhythm Case Reports 2016;2:283
  • 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 (2015;12:180-182)
  • 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 EType 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, Wong T, Peters NS. Too focused? The perils of a fashionable diagnosis. J Cardiovasc Electrophysiol 2002;13:1058-60
  • 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, 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

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