More malignant than cancer?
In anticipation of Heart Failure Awareness Day on 10 May, Oxford University Press has pulled together information across the press to provide resources on heart failure. We’re also running a series of blog posts on this dangerous disease. To kick us off today, we chatted with Professors Theresa MacDonagh, past Chair of the British Society for Heart Failure, and Andrew Clark, Chair-elect, about the diagnosis of heart failure and the importance and benefit of adequate treatment.
So what is heart failure?
Andrew Clark: It sounds terrible, doesn’t it? It must be an awful thing for a patient to hear during a consultation as it sounds on the face of it as if the heart is about to stop. That’s absolutely not what it means, of course. Heart failure is just the term used to describe the situation in which the heart does not pump as strongly as it should to drive blood round the body. The consequences can be dramatic: if heart failure develops suddenly, then a patient can develop fluid in their lungs, called pulmonary oedema, very rapidly; but more commonly, patients gradually retain fluid and present with breathlessness and swollen ankles. It’s a very common reason for people to be referred to medical clinics at hospital.
Theresa MacDonagh: I think that makes the point that it’s important for patients to have someone with them when they first encounter heart failure. It’s a complex disease, and whilst medical treatment is hugely beneficial, there’s a lot of information to take in. Education of the patient and their supporters is a key part of good management.
What are the causes of heart failure? How common is it?
Andrew Clark: Well, the most common cause of heart failure is one or more previous heart attacks. This is the cause in perhaps a half of patients. During a heart attack, some of the heart muscle itself dies and is replaced by scar tissue. Enough heart muscle can be damaged that heart failure develops. A cause in about a third of patients is dilated cardiomyopathy in which all the heart muscle is damaged by a disease process. It’s not completely clear how this happens: in some people there is a genetic cause, in others an infective one. In many cases, we simply don’t know as yet. There are many other less common causes of heart failure, such as heart valve disease.
Heart failure is very common. As your work showed, around 1% of the population have heart failure due to impairment of the pump function of the heart, and another 1% have damage to the heart but have no symptoms.
Theresa MacDonagh: The diagnosis of heart failure carries such a bleak prognosis. We know from data collected for the National Heart Failure Audit that around a third of patients being discharged from hospital after an admission for heart failure will die during the subsequent year.
What treatment is there, or is it just a diagnosis with no hope?
Andrew Clark: The fluid retention of heart failure can usually be managed quite straightforwardly with diuretics, medications that make the kidneys produce more urine. The more profound treatment, though, arises from the realisation that heart failure causes many of the body’s natural hormonal systems to be greatly activated. Patients with heart failure have high levels of adrenaline and a closely related chemical, noradrenaline, in the circulation, together with other hormones, particularly angiotensin II and aldosterone. High levels of hormones are implicated in the progression of heart failure and eventual death.
The mainstays of modern medical therapy are blockers of these hormones, particularly betablockers (such as carvedilol), angiotensin converting enzyme inhibitors (such as ramipril) and mineralocorticoid receptor antagonists (such as spironolactone). Used together, these drugs have a profound effect on the outlook of patients with heart failure and can approximately double life expectancy.
Theresa MacDonagh: We should also mention the role of implantable devices, such as defibrillators, which can stop life-threatening fast heart rhythms by administering an internal electric shock, and cardiac resynchronisation pacemakers, or CRT, which can improve the overall function of the heart in selected patients. Both can improve outlook, and CRT can result in a dramatic improvement in exercise capacity.
Andrew Clark: One of the main challenges for heart failure cardiologists is devising care pathways and systems to get this therapy to as many patients as possible. Indeed, and that’s one of the major aims of the Heart Failure Audit and the British Society for Heart Failure.
What information is there available for patients and their carers?
Theresa MacDonagh: There can be a bewildering amount of information on the web which can be very unhelpful and give conflicting advice. One excellent resource is the site run by the European Society of Cardiology, Heart Failure Matters, which is well-written and emphasises individual patient experience as well as being a comprehensive factual resource.
Andrew Clark is Professor of Clinical Cardiology in the University of Hull. He trained in Manchester, London and Glasgow, and has research interests in exercise physiology and clinical aspects of heart failure. He is Chair-elect of the British Society for Heart Failure. Theresa A. McDonagh is a consultant cardiologist at King’s College Hospital in London, UK. They are the editors of the Oxford Textbook of Heart Failure with Roy S. Gardner and Henry Dargie.
Oxford University Press is supporting Heart Failure Awareness Day with resources from across the press.
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Image credit: Male anatomy of human organs in x-ray view. Image by janulla, iStockphoto.