Photo of Dr John Malcolm Walker

Dr John Malcolm Walker

Email:

Location:

  • University College Hospital

GMC/GDC number:

2234618

Professional background

I qualified in Medicine from the University of Birmingham with honours in pre-clinical medicine and obtained an MD from that institution in 1984. My clinical training in cardiology began at St Thomas’ Hospital London and completed in Oxford before I was appointed consultant cardiologist and physician at University College Hospital London (UCLH) in 1987. I have maintained a comprehensive clinical cardiology practice at UCLH, the Middlesex and the Heart hospitals, encompassing all aspects of adult cardiology and intervention, with periods as the clinical director and latterly, the clinical lead for cardiology services.

In 1990 I co-founded with my non-clinical scientist colleague, Dr Derek Yellon, the Hatter Cardiovascular Institute (HCI), utilising donations from a charitable trust. This Institute moved into a bespoke building in 2006, where clinical service and laboratory cardiovascular research are housed in close physical proximity. The HCI has an international reputation in laboratory and translational research focusing on myocardial protection, producing >600 publications and over 70 MD and PhDs since its inception.

In 1990 I established a cardiology clinic for patients with disorders of haemoglobin. Out of this clinical service arose the interest in iron overload, which led to the development of the MRI T2* parameter for non-invasive tissue iron assessment. Clinical use of T2* has been associated with a >70% reduction in cardiovascular mortality in thalassaemia patients. I have written the chapters on cardiac management of thalassaemia for the UK National Standards Framework and for the International Guideline published by TIF. I was an expert contributor to the AHA consensus statement on the management of cardiovascular complications of thalassaemia, published in Circulation 2013 and still the standard reference article for the care of TM patients.

In recent years I have ceased cardiology interventional practice to focus on the cardiovascular complications of thalassaemia and cardiac involvement in cancer. In 2016 I helped establish the cardio-oncology service at UCLH. This is an expanding clinical service and research programme, serving cancer patients with cardiovascular complications.

I have published over 100 articles in major scientific journals & have a Scopus H-index of 36.

Specialties

Research interests

  • General adult clinical cardiology, including coronary intervention and pacemaker therapy
  • Cardiovascular rehabilitation and prevention
  • Cardiovascular complications of inherited diseases of haemoglobin, specifically the thalassaemia syndromes and sickle cell disease.

Languages spoken

Spanish

Publications

Selected publication list
1. Anderson, L.J., Holden, S., Davis, B., Prescott, E., Charrier, C.C., Bunce, N.H., Firmin, D.N., Wonke, B., Porter, J., Walker,J.M., Pennell, D.J.(2001) Cardiovascular T2-star (T2*) magnetic resonance for the early diagnosis of myocardial iron overload, EUROPEAN HEART JOURNAL, 22, 2171-2179.
Comment: The article establishing the MRI T2* parameter as a viable non-invasive measure of myocardial iron load in heart and liver.

2. Walker,J.M., (2012) Thalassaemia major and the heart: a toxic cardiomyopathy tamed? Heart, 99; 827-834.
Comment: A review article concerning iron overload related cardiomyopathy and emphasizing its capacity for complete resolution by iron chelation and proposing this as a useful model to study myocardial adaptation and repair.

3. Pennell, D.J., Udelson, J.E., Arai, A.E., Bozkurt, B., Cohen, A.R., Galanello, R., Hoffman, T.M., Kiernan, M.S., Lerakis, S., Piga, A., Porter, J.B., Walker,J.M., Wood, J., (2013) Cardiovascular Function and Treatment in beta-Thalassemia Major: A Consensus Statement From the American Heart Association, Circulation, 128, 281-308.
Comment: A review and management plan for the cardiovascular complications of thalassaemia, achieved by consensus and remaining the reference article for most national and international guidelines.

4. Abdel-Gadir, A., Vorasettakarnkij, Y., Ngamkasem, H., Nordin, S., Ako, E.A., Tumkosit, M., Sucharitchan, P., Uaprasert, N., Kellman, P., Piechnik, S.K., Fontana, M., Fernandes, J.L., Manisty, C., Westwood, M., Porter, J.B., Walker,J.M., Moon, J.C., (2016) Ultrafast Magnetic Resonance Imaging for Iron Quantification in Thalassemia Participants in the Developing World: The TIC-TOC Study (Thailand and UK International Collaboration in Thalassaemia Optimising Ultrafast CMR), Circulation, 134, 432-434.
Comment: The first of a series of articles establishing the rapid cardiac MRI methodology (rCMR) in low and middle income countries.

5. Ghosh, A.K. and Walker,J.M., (2017) Cardio-oncology, British Journal of Hospital Medicine, 78, C11-C13.
Ghosh, A.K., Manisty, C., Woldman, S., Crake, T., Westwood, M., Walker,J.M., (2017) Setting up cardio-oncology services, Br J Cardiol, 24, 1-5.

6. Ghosh, A.K. and Walker,J.M., (2017) Cardio-Oncology A new subspecialty with collaboration at its heart, Indian Heart Journal, 69, 556-562. Comment: A series of articles establishing cardio-oncology practice