Professor Mark O’Neill is a Consultant Cardiologist and Electrophysiologist at St. Thomas’ Hospital London and Professor of Cardiac Electrophysiology at King’s College London. He qualified with first class honours from University College Dublin Medical School in 1998, having completed his DPhil in Cardiac Physiology as a Rhodes Scholar at Oxford University in 1995. He undertook subspecialty training in interventional cardiac electrophysiology at St Mary’s Hospital and in 2005 undertook a British Heart Foundation fellowship in the world-renowned arrhythmia centre in Bordeaux where he gained particular expertise in catheter ablation of atrial fibrillation.
He joined St Thomas’ Hospital and King’s College London as a consultant in the Department of Cardiology and Division of Imaging Sciences and Biomedical Engineering in 2009. He was promoted to Reader in 2011 and Professor in 2013 and has since led the arrhythmia service, regional training programme and divisional research programme in cardiac electrophysiology. In 2016, in recognition of the quality and breadth of his clinical and academic work, he received a National Bronze Clinical Excellence award.
Professor O'Neill is an international opinion leader in cardiac electrophysiology, is actively involved in research and has published over 200 papers in peer-reviewed journals. His research addresses the mechanisms of atrial fibrillation and the use of novel mapping, imaging and computational modelling techniques to better understand the reasons why a patient develops AF and therefore how best to manage it.
He lectures regularly in the UK and abroad on atrial arrhythmia management. He treats patients with simple and complex heart rhythm disturbances of atrial and ventricular origin, in particular atrial fibrillation and tachycardia in the context of inherited and acquired structural heart disease.
His private practice is based at The Heart Rhythm Clinic, 88 Harley Street. He performs interventional electrophysiology procedures at the Harley St Clinic.
In June 2018, the Daily Mail published the profiles of the top ten UK electrophysiologists recommended by cardiologists themselves. About Professor O'Neill, his peers were quoted as saying: "On the leading edge, he has built an international reputation based on his prolific research work. He is also known to provide a measured opinion on what is best for patients. He is an extremely astute doctor, particularly in diagnostics. He will look at patients very objectively and pick up very subtle clinical signs that others will overlook."
At the Heart Rhythm Clinic, Professor O'Neill will give you the time to help you understand your symptoms and reach a diagnosis. He will provide treatment advice and expertise in partnership with you and tailored to your concerns.