Mark O’Neill

Mark O’Neill

Consultant Cardiologist and Professor of Cardiac Electrophysio

St Thomas’ Hospital and King’s College London, London, UK

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Consultant Cardiologist and Professor of Cardiac Electrophysio, St Thomas’ Hospital and King’s College London, London, UK

Professor Mark O’Neill completed his undergraduate medical and postgraduate scientific training at University College Dublin and the University of Oxford. In 2005, Dr O’Neill undertook a specialist training fellowship in cardiac electrophysiology in Bordeaux with Professors Michel Haissaguerre and Pier Jais, specifically to develop expertise in catheter ablation of atrial fibrillation. Dr O’Neill joined Guy's and St Thomas' in 2009 where he now leads the clinical research group in cardiac electrophysiology.

Research Interests:

  • Comparison of fibrosis determined by MRI and electrical conduction properties.
  • Evaluation and study of ablation lesions using MRI.
  • Use of new catheter technologies for ablation.
  • We believe that an interdisciplinary approach will accelerate progress, ultimately leading to better, safer and more permanent treatments for patients with cardiac arrhythmias.


Anisotropic Cardiac Conduction

Irum D Kotadia, John Whitaker, Caroline H Roney,


Citation: Arrhythmia & Electrophysiology Review 2020;9(4):202–10.

High-power, Short-duration Radiofrequency Ablation for the Treatment of AF

Irum D Kotadia, Steven E Williams, Mark O’Neill,


Citation: Arrhythmia & Electrophysiology Review 2019;8(4):265–72.

Increasing the Single-Procedure Success Rate of Pulmonary Vein Isolation

Mattias Duytschaever, Mark O’Neill, Martin Martinek,

Citation: Arrhythmia & Electrophysiology Review 2017;6(4):217–21.

Cardiac Electrophysiology Under MRI Guidance: an Emerging Technology

Henry Chubb, Steven E Williams, John Whitaker,

Citation: Arrhythmia & Electrophysiology Review 2017;6(2):85–93

Pacing and Defibrillators in Complex Congenital Heart Disease

Henry Chubb, Mark O’Neill, Eric Rosenthal,

Citation: Arrhythmia & Electrophysiology Review 2016;5(1):57–64

Pathophysiology and Management of Arrhythmias Associated with Atrial Septal Defect and Patent Foramen Ovale

Henry Chubb, John Whitaker, Steven E Williams,

Citation: Arrhythmia & Electrophysiology Review 2014;3(3):168–72