Dr Dewi Thomas

Dr Dewi Thomas

Consultant Cardiologist and Electrophysiologist


Specialises in

  • Heart rhythm management
  • Pacemaker implantation

I am a Consultant Cardiologist and Electrophysiologist at Morriston Hospital Regional Cardiac Centre and was appointed to this post in September 2016.

I specialise in all aspects of heart rhythm management including the use of catheter ablation to treat arrhythmias such as Atrial Fibrillation, SVT and Ventricular Tachycardia. Since my appointment I’ve helped lead the expansion and development of ablation services in the region, resulting in Morriston becoming the highest volume EP centre in the country.

I graduated from the University of Edinburgh in 2002, and completed junior doctor training in Edinburgh and South Wales. In 2012 I was awarded a research doctorate (MD) by Cardiff University, and in 2016 I completed an advanced clinical fellowship in Electrophysiology at the James Cook University Hospital, Middlesbrough.

Cardiac Electrophysiology is also devoted to the implantation and follow-up of pacemakers, defibrillators and resynchronisation devices and I have a strong clinical and research background in this area too. During my fellowship training I worked as part of a team to deliver the UK’s first leadless ultrasound-based pacemaker, and more recently I established Wales’ first Conduction system pacing programme.

The other area of medicine that’s very important to me is education, and I’m heavily involved in medical education on a local and national level. I am a senior lecturer and clinical lead for cardiovascular medicine at Swansea University Medical School, and represent Wales on the British Heart Rhythm Society’s education committee where I’ve been helping to set the national accreditation exams for the last 6 years. This work compliments my clinical activities and I hope enhances my ability to explain and promote understanding during my patient interactions.

I hold international accreditation through British, American and European heart rhythm societies, in invasive electrophysiology and implantable device therapy. I am extensively published in peer reviewed journals and regularly invited to speak at national and international meetings.


General Medical Council Number: C6050337

Treatment information

Some of the principal treatments carried out by Dr Dewi Thomas at Spire include:


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Additional information

Arrhythmia (Electrophysiology)
Atrial fibrillation

Special Clinical Interests: Cardiac Electrophysiology, encompassing the investigation and treatment of all arrhythmias; Palpitations and blackouts; Ablation of Supraventricular Tachycardias (SVT); Ablation of complex arrhythmias including Atrial Fibrillation (AF) and Ventricular Tachycardia (VT); Heart Failure; Implantable cardiac devices including Pacemakers, Biventricular pacemakers (CRT) and Defibrillators (ICDs).

MbChB / Edinburgh University Medical School / 2002
Bachelor of Medicine, Bachelor of Surgery

MRCP / Royal College of Physicians of London / 2006
Royal College of Physicians

MD / Cardiff University / 2012
Doctorate of Medicine

Certificate of Completion of Training in Cardiology / Wales / 2014
Wales Deanery

CCDS / International Board of Heart Rhythm Examiners / 2014
Certified Cardiac Device Specialist

ECES / European Heart Rhythm Association / 2016
Certified Electrophysiology Specialist

Professional memberships

Member of the Royal College of Physicians

Member of the British Heart Rhythm Society

Professional leadership

Clinical Tutor for Cardiology, Swansea University Medical School
Consultant Cardiologist and Electrophysiologist, Morriston Regional Cardiac Centre

Book Review - The EHRA book of pacemaker, ICD, and CRT troubleshooting Br J Cardiol; November 2015, B2015;22:133 What can be learnt from the ESC 2009? Cardiology News Feb 2010


Insights from a Small Wobble. Thomas DE, Suran BM, Leong FT

Heart rate deceleration after exercise predicts patients most likely to respond to cardiac resynchronisation therapy. Thomas DE, Exton SA, Yousef ZR

The value of using fractional flow reserve measurements in helping to diagnose acute left ventricular failure in the presence of normal left ventricular systolic function. Thomas DE, Yousef ZR, Kinnaird TD, Anderson RA.

Blood vessel specific vasoactivity to nitrite under normoxic and hypoxic conditions. Ingram TE, Pinder AG, Milsom AB, Rogers SC, Thomas DE, James PE

Routine issuance of clinical magnets to patients receiving implantable defibrillators: retention of information and appropriateness of use. Thomas DE, Barry JP, Churchouse W, Anderson MH.

Can isovolumic acceleration be used in clinical practice to estimate ventricular contractile function? Reproducibility and regional variation of a new noninvasive index. Margulescu AD, Thomas DE, Ingram TE, Vintila VD, Egan MA, Vinereanu D, Fraser AG.

A critical comparison of echocardiographic measurements used for optimizing cardiac resynchronization therapy: stroke distance is best. Thomas DE, Yousef ZR, Fraser AG.

Cardiac resynchronization therapy in coronary sinus atresia delivered using leadless endocardial pacing. Thomas DE, Child NM, Owens WA, Linker NJ, James SA, Turley AJ.

Ventricular Arrhythmias in Acute Coronary Syndromes – Mechanisms and Management. Thomas DE, Jex N, Thornley AR.

Cardiology Education. 2017 March; 3(1):22-29 Combined subpectoral implantation of a cardioverter defibrillator and breast augmentation surgery in a patient with Emery-Dreifuss muscular dystrophy. Thomas DE, Murison MS, Anderson MH. Future Cardiol. 2015 May;11(3):293-5.

Pacemaker Implantation in Superior Vena Cava Obstruction: Re-canalisation, Venoplasty and Stenting. Thomas DE, Thanh T P, Hartley R, Linker NJ, Muir DF, Turley AJ. Journal of Cardiology Cases. 2016 July; 14:29–31.

The role of echocardiography in guiding management in dilated cardiomyopathy. Thomas DE, Wheeler R, Yousef ZR, Masani ND. Eur J Echocardiogr. 2009 Dec;10(8):iii15-21.

Novel pharmacological interventions to maintain sinus rhythm after DC cardioversion. DE Thomas, ZR Yousef, RA Anderson. ISRN Cardiology (2011), Article ID 176834

Heart Rhythm Conundrum. Davies RH, Thomas DE. British Medical Journal

Telephone 02920 542 509
Private secretary Mrs Kim Lake
Private secretary telephone 01792 532 107
Private secretary email kim.lake@wales.nhs.uk