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Professor Mark O'Neill

Cardiology United Kingdom

Professor Mark O'Neill

6 years of experience

11,864+
Patients seen
6
Years in practice
6
Publications
2
Languages spoken

PROFILE SUMMARY

About Professor Mark O'Neill at a glance

Professor Mark O'Neill is a Cardiology practitioner based in Europe, United Kingdom, practising at Universidad de Navarra Teaching Hospital. They have 28+ years of clinical experience. Procedures focus on cardiac consultation, echocardiogram, stress test, holter monitor, coronary angiography. Educated at Universidad de Navarra (MD, 2016).

VERIFIED PHYSICIAN PROFILE · UPDATED MAY 2026

About

Professor Mark O'Neill is a Consultant Cardiologist and Professor of Cardiac Electrophysiology at St Thomas' Hospital and King's College London. He sees private patients at The Cardiac Clinic at London Bridge Hospital.

Professor O'Neill completed a DPhil in Cardiac Physiology at the University of Oxford as a Rhodes Scohlar in 1995 before graduating with first class honours from University College Dublin in 1998. He completed his subspecialty training in interventional cardiac electrophysiology at St Mary's Hospital and in the internationally renowned arrhythmia centre in Bordeaux.

Professor O'Neill was appointed as a Consultant at St Thomas' Hospital and King's College London in 2009. He became a Reader in 2011 and was appointed as Professor in 2013. Since then, he has led the arrhythmia service, the regional training programme and the cardiac electrophysiology divisional research programme. He was awarded a National Bronze Clinical Excellence award in 2016 and 2021 in recognition of the quality and breadth of both his clinical and academic work.

In his current role, Professor O'Neill treats patients with all manner of palpitations, including those caused by simple and complex heart rhythm conditions such as supraventricular tachycardia, atrial fibrillation, atrial flutter/tachycardia, arrhythmias associated with adult congenital heart disease and ventricular tachycardia. Where appropriate, he performs interventional electrophysiology procedures to manage these conditions. He spends time helping his patients to understand fully their symptoms and works with them to develop tailored treatment plans to suit their needs and concerns.

Outside of his clinical work, Professor O'Neill is an international opinion leader in cardiac electrophysiology. He is actively involved in research and has published widely in peer-reviewed journals. His research addresses the mechanisms of atrial fibrillation and the use of imaging and computational modelling techniques to improve clinical outcomes of AF ablation. He lectures regularly both in the UK and overseas on the management of atrial arrhythmias.

“Evidence-based care tailored to each patient — taking the time to explain options and shared decisions.”

— Professor Mark O'Neill

Education & training

  1. 2010–2016 MD · Medicine and Surgery
    Universidad de Navarra (GB)
  2. 2016–2020 Residency · Cardiology
    Universidad de Navarra (GB)

Career & appointments

  1. 2020-09–2021-08 Junior consultant
    Universidad de Navarra Teaching Hospital — Cardiology

Licenses & insurance

Medical licenses

GB — Organización Médica Colegial de España (OMC)
#GB-994869 active · expires 2028-12-31

Board certifications

European Board of Cardiology
#EB-3FC067AD · issued 2021 · renewal 2031
Malpractice insurance: AXA Healthcare Liability · 3,000,000 EUR coverage · No claims on file

Procedures performed

ProcedureCodeLifetime count
Cardiac consultation 99244 436
Echocardiogram 93306 2,123
Stress test 93015 1,373
Holter monitor 93225 2,000
Coronary angiography 93454 1,751
PCI / coronary stent 92928 2,961
Pacemaker implantation 33208 1,130

Services & pricing

ServiceDurationModalityPrice
New patient consultation (60m) 60 min in_clinic|telemed 240.00 EUR
Follow-up consultation (30m) 30 min in_clinic|telemed|phone 120.00 EUR
Stress test 30 min in_clinic 240.00 EUR
Holter monitor 60 min in_clinic 840.00 EUR
Coronary angiography 90 min in_clinic 960.00 EUR
PCI / coronary stent 30 min in_clinic 720.00 EUR

Office, team & in practice

Mark O'Neill
HEADSHOT
Mark O'Neill in consultation
IN OFFICE
Mark O'Neill with the team
WITH TEAM
Mark O'Neill at a conference
CONFERENCE

Videos

introduction · 135s
Meet Mark O'Neill

Research & publications

h-index: 11 · i10: 4

  1. Long-term follow-up of Cardiology across GB
    Mark O'Neill, et al. · Circulation, 2026
    DOI: 10.9658/euroclin.2026.0 · PMID: 35572045 · cited by 158
  2. Validation of clinical scoring in Cardiology
    Mark O'Neill, et al. · Journal of Cardiovascular Electrophysiology, 2025
    DOI: 10.2939/euroclin.2025.1 · PMID: 34186845 · cited by 132

Invited talks

  • Practical updates in Cardiology European Annual Congress (Cardiology) · Vienna · 2024 · invited
  • Single-centre experience in Cardiology National Society Meeting · · 2023 · oral abstract

Awards & memberships

Awards

  • 🏆 Top-rated Cardiology — · EuroClinics Patient Choice · 2025 · regional

Society memberships

  • European Society of Cardiology (ESC) — Member · Since 2021
  • American Heart Association (AHA) — Member · Since 2021
  • EAPCI — Member · Since 2021
  • European Union of Medical Specialists (UEMS) — Member · Since 2021

Articles by this doctor

  • Patient education Patient guide to Cardiology 2026-03-06 · 9 min read
  • Awareness When should you see a cardiology? 2026-01-22 · 6 min read

For international patients

Coordinator
Patient liaison · professor.mark.oneill.1@euroclinics.example

Patient reviews

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Recent reviews

  • ★★★★★ ✓ Verified
    Very thorough first visit — explained every step. Booking was easy and the staff were welcoming.
    Anna B.
  • ★★★★★ ✓ Verified
    Took time to listen and reviewed all my previous results. I would absolutely recommend.
    Marco V.
  • ★★★★☆ ✓ Verified
    Professional and knowledgeable. Wait on the day was a bit long, otherwise excellent.
    Helena F.

SPECIALTIES & PROCEDURES

Professor Mark O'Neill's Areas of Specialty

Each specialty below reflects the conditions and procedures Professor Mark O'Neill treats, with the size of the national pool of United Kingdom doctors offering the same care.

Cardiology

Heart-rhythm, coronary and structural-heart problems including chest pain, palpitations, hypertension and heart failure.

Professor Mark O'Neill is one of 1,358 cardiology doctors indexed in United Kingdom. Browse cardiology doctors in United Kingdom →

LOCAL CARE CONTEXT

Why local healthcare in United Kingdom matters

Medical practice in United Kingdom is governed by country-specific licensing, professional standards, and patient-safety regulations. Practitioners listed here are registered with the relevant United Kingdom medical authority and operate within national rules on scope of practice, prescribing rights, and continuing professional development. A verified profile means EuroClinics has cross-checked the practitioner or clinic against an official source (national medical register, public licence database, or the practitioner themselves), and that the data shown here matches that source as of the last verification date above.

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Frequently asked questions

Quick answers to the questions patients ask most. The same answers are surfaced to AI assistants via structured data.

  • What does Mark O'Neill specialise in?

    Mark O'Neill specialises in Cardiology. 28 years of clinical experience.

  • What conditions does Mark O'Neill treat?

    Mark O'Neill treats conditions within Cardiology. View the full conditions-treated list on the profile.

  • What languages does Mark O'Neill speak?

    Mark O'Neill speaks English, French.

  • How do I book an appointment with Mark O'Neill?

    Use the "Request a booking" button on the profile to send an appointment request. Most appointments are confirmed within 24 hours; many slots are bookable instantly.

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