Contact details

Dr Darrel P Francis

Reader in Cardiology
National Heart & Lung Institute

Tel: +44 (0)20 7594 1093
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Dr Darrel Francis

Darrel Francis is a Reader in Cardiology at the National Heart and Lung Institute. He specialises in studying the use of quantitative techniques, derived from mathematics, engineering and statistics, to problems that affect patients with heart disease.

Throughout his training in Medical Sciences in Cambridge and clinical training as a Junior Doctor in Oxford, he concentrated on trying to understand mechanisms of disease (and diagnosis) in quantitative terms.

He moved to Imperial College London for his thesis funded by a British Heart Foundation Junior Research Fellowship, which was the application of mathematical techniques to cardiorespiratory interaction, and then completed his Clinical Specialty training in Cardiology here.

Research and Teaching at Imperial College

In 2005 Dr Francis started a 10-year programme of research at Imperial, supported by the British Heart Foundation, in which he focuses on applying his approaches to several problems in cardiology:

Cardiac "Resychronization" Therapy: Really?

We now implant tens of thousands of biventricular pacemakers into patients in heart failure: they improve symptoms and save lives. But it is far from clear how they do this.

It is conventionally believed that the benefit they give is principally by making the different parts of the ventricle contract at the same time, hence the name "resynchronization" and the snappy Three Letter Acronym (TLA) of CRT.

But when large, externally-regulated trials have tested whether the size of the benefit is related to the amount of dyssynchrony a patient has, they have found a very low correlation. This is alarming because if we select patients for an intervention according to a numerical criterion (X is greater than a threshold value) and yet there is no gradation of benefit from intervention across our selected group group (i.e. patients with very high X's don't benefit any more than patients with slightly high X's) then this means one of two things:

1. The selection test works perfectly - patients scoring more than X will respond strongly while those scoring less than X will not respond - but this happy situation virtually never happens in medicine or in biology, and we should not assume that this is one such rare circumstance
2. X does not tell us much about who will benefit, and perhaps quite a few people who might benefit are being left out, while perhaps quite a few people who won't benefit are being treated.

When reality does not match up with a mental model, it is the mental model, and not reality, that is wrong.

Dr Francis and his clinical research fellows Dr Zachary Whinnett and Dr Andreas Kyriacou are using detailed physiological experiments, as well as access to data from large studies provided by international collaborators, to explore the mechanism by which these devices give their benefits, so that we can better understand what exactly it is we are doing.

When is an optimization not an optimization?

Guidelines recommend that all biventricular pacing devices undergo optimization of their settings after implantation. Typically this means making adjustments while observing the function of the heart, by monitoring blood flow (echocardiogaphy) or pressure (pressure sensor) and then selecting the setting which gives the most flow or pressure.

However, the guideline-recommended techniques do not do what they promise to do. First, real cardiologists are unable to agree which setting is best, even when presented with the indentical data. Second, the guidelines have been developed without regard to the presence of random variability, which makes it necessary to make multiple measurements or a special algorithm in order to ensure that the optimum selected is really the right one. Third, when the mathematics is examined, it becomes clear that it would take a procedure lasting hours or days in many patients to reliably optimize their pacemakers.

As a result, the guideline-recommended optimization algorithms are in about half of cases actually worsening the efficiency of the heart, rather than improving it.

Dr Francis and his research fellow Dr Punam Pabari, together with international collaborators, are developing a "basic science of optimization". This includes an explicit recognition of the presence of noise as well as signal, and treats these quantitatively so that clinicians can have something better than wishful thinking to aid them. Once completed, this programme of research will provide tools so that clinicians worldwide can reliably evaluate their own local optimization procedures and then conduct optimization confident in the knowledge that the process is not merely placebo.

Evolving interests

As the years passed his academic interests have widened and intensified through growing collaborations within Imperial College and internationally, and he has taken on additional projects, including:

- trying to improve training support for physiologists learning to carry out echocardiography

- improving the understanding of exercise physiology in chronic heart failure

- examining the flow patterns of mitral regurgitation to help guide treatment more reliably

- evaluating 3d echocardiography in potentially dyssynchronous hearts

- comparing different forms of plethysmogram for monitoring haemodynamics in heart failure

Imperial College has recently appointed him Theme Leader within the Imperial-BHF Centre for Research Excellence in recognition of this extensive collaborative teaching and research work at South Kensington and St Marys Campuses and also across Europe and beyond.

Honorary NHS Consultant Cardiologist - St Mary's Hospital

In parallel with his academic role with Imperial College, Dr Francis also has an honorary role as Consultant Cardiologist at St Marys Hospital. This work is an important adjunct to his research and teaching roles with Imperial College, because it makes him keep in the forefront of his mind the day-to-day problems faced by cardiology patients and their physicians.

He deals with cardiac emergencies at the hospital and carries out early-morning ward rounds of Cardiology patients. His own inpatients are in the Queen Elizabeth Queen Mother building in the Coronary Care, General Cardiology, and Intensive Care wards, as well as in the medical admissions areas.

He conducts and analyses tests on Cardiology patients, including echocardiography, stress echocardiography and cardiopulmonary exercise testing, and his special expertise is in cardiopulmonary interaction.

Emergency treatment of heart attack victims by primary angioplasty is another specialised role which he now has the honour to participate, which allows him to stay fully active in clinical practice while conserving daytime hours for research and teaching work.

In 2009 he was awarded the Fellowship of the Royal College of Physicians.

Cardiology Specialist Trainees

Aside from research, teaching, clinical practice as a cardiologist, and dodging administrative activities, Dr Francis' other long-term interest is in guidance of cardiology trainees before, during and after clinical training programme, and especially in encouraging them to pursue academic interests in parallel with clinical training.

Dr Francis is committed to enhancing Imperial College's recognised position as the most attractive location in the UK for those wishing to pursue such a dual path. He has been recognised by the Rector of Imperial College for his commitment to mentoring, and is Deputy Training Programme Director and Academic Cardiology Advisor for the 65 Cardiology Specialist Trainees in the Imperial College sector of London.

Selected Publications