Mark O'Neill

Mark O'Neill, Consultant cardiologist and professor of cardiac electrophysiology

Consultant cardiologist and professor of cardiac electrophysiology


Mark O'Neill was appointed consultant at St. Thomas’ Hospital in 2009. Since then he has built an international reputation for the unit in the field of atrial arrhythmia research and interventional management.

In addition to his day-to-day clinical work as a heart rhythm specialist, Mark is also the joint Clinical Director of the Trust’s Cardiovascular Directorate.

Education and training

  • Fellowship of the Royal College of Physicians, 2012
  • Fellowship of the Heart Rhythm Society, 2011
  • Certificate of completion of specialist training in cardiology, 2007
  • Membership of Royal College of Physicians, 2001
  • Medicine and surgery (MB BCh), First-Class Honours, University College Dublin, 1998
  • DPhil in physiological sciences, Rhodes Scholar, University of Oxford, 1995

Research interests

In 2009, he joined King’s College London School of Biomedical Engineering and Imaging Sciences (BMEIS) and was promoted to Professor in 2013. His research group integrates clinical and computational research methodologies in signal processing and cardiac imaging to improve arrhythmia characterisation and treatment in patients with heart rhythm disturbances.


  • 2021 – Renewal Bronze National Clinical Excellence Award

  • 2016 – Bronze National Clinical Excellence Award

  • 1998 – Inaugural Rhodes European Scholarship (Ireland)

Twenty five academic prizes at medical school including:

  • RCPI Reuben Harvey prize for Medicine
  • Surgery and Obstetrics in the Dublin Medical Schools (1998)
  • First place in five of six years including final year

Last updated: June 2023

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