What is ejection fraction ?
What is heart failure?
A heart is a pump that takes blood from the veins and pumps it to the rest of the body via arteries. If its pumping action is impaired, blood stays in the veins, creating back-pressure and swelling. In addition, the body compensates for this by secreting hormones that promote water retention. In the lungs, vein swelling eventually leads to leakage of water into the lung tissues – ‘water in the lungs’, or pulmonary oedema. In the legs, leakage of water into the tissues leads to ankle swelling, or ankle oedema. Heart failure is said to occur when pulmonary and leg oedema occur as a result of a problem with the pumping action of the heart. Sometimes the pumping action of the heart is impaired, but not sufficiently so as to cause swelling of the veins and seepage of fluid into the lungs and legs.
There are two types of heart failure:
• Systolic heart failure: occurs when the heart muscle does not contract properly. It is also called Heart Failure with reduced Ejection Fraction (HFrEF).
• Diastolic heart failure: occurs when the contraction is normal, but the relaxation is slow. It is also called Heart Failure with Preserved Ejection Fraction (HFpEF).
What causes heart failure?
Conditions that affect the muscle of the heart, the heart valves or the electrical tissue of the heart can potentially cause heart failure. The commonest causes include:
• Myocardial infarction (heart attack): a condition that occurs when a coronary artery is blocked. When this occurs, there is permanent damage to heart muscle.
• Cardiomyopathy: conditions that result in damage to the heart muscle, but which exclude damage from heart attacks.
• Hypertension (high blood pressure): a condition that puts strain on the heart muscle, leading to thickening of the heart muscle and dilation of the heart.
• Valve disease: conditions that lead to damage of the heart valves lead to untoward pressure changes within the heart.
• Heart defects present at birth (congenital heart disease): an abnormally structured heart causes abnormalitites of blood flow and increased pressure within the heart chambers.
It is essential that you are investigated for heart failure is, so that the right treatments can be considered.
What are the symptoms?
The symptoms include:
• Breathlessness: This can be due to accumulation of fluid in the lungs (pulmonary oedema), but can also occur in its absence. When there is fluid in the lungs, a cough or wheezing can occur.
• Fluid retention (oedema): In heart failure, the kidneys respond by promoting the retention of fluid. This collects in the most dependent parts of the body, ie. the legs. Passing urine at night, breathlessness on lying down (orthopnoea) and waking up at night gasping for air (paroxysmal nocturnal dyspnoea) can also occur.
• Fatigue: this results from a reduction in the blood suppy to all parts of the body.
• Palpitations: As the heart tries to compensate for the reduction in blood supply, it speeds up and this is felt as rapid or irregular heartbeats.
How do we detect heart failure?
Doctors can diagnose heart failure by taking a history and examining the patient. Often, investigations are needed to explore what has caused heart failure and how best to treat it.
• ECG (heart trace): Although the ECG does not confirm the diagnosis of heart failure, it is more than likely abnormal in patients with the condition. It can reveal previous heart attacks and disorders of heart rhythm.
• NT pro-natriuretic peptide (NT pro-BNP) blood test. This hormone is secreted from the heart when it stretches in an abnormal fashion. High levels make heart failure more likely, but it does not confirm the diagnosis. A low BNP test makes heart failure unlikely.
• Chest X-ray: A chest X-ray can give an approximation of the size of the heart and can show whether there is fluid in the lungs (pulmonary oedema and pleural effusions). It does not, however, provide information of heart function.
• Echocardiogram: This provides a very comprehensive assessment of the heart structures and function. It should be performed for the diagnosis and monitoring of heart failure.
• Cardiac MRI scan: This specialised scan provides very accurate information on heart function and the causes of heart failure.
• Cardiac catheterisation: This may required to assess the cause of heart failure.
What is the treatment ?
Traditionally, heart failure has been treated only with drugs. Over the past decade, however, the treatment of patients with heart failure has been revolutionised by cardiac device therapy – cardiac resynchronisation therapy (CRT) and implantable cardioverter defibrillators.
These are designed to relieve swelling and to improve the function of the heart. Here are some examples:
• Diuretics (water tablets), such as furosemide and bumetanide relieve breathlessness and ankle swelling by getting rid of fluid.
• ACE inhibitors, such as ramipril and perindopril, reduce blood pressure in the arteries and improve the pumping action of the heart.
• Beta-blockers, such as bisoprolol and carvedilol, slow down the heart rate and neutralise the undesirable effects of substances released by the body when the heart fails.
• Aldosterone receptor blockers (ARBs), such as spironolactone and eplerenone, counteract the effects of a harmful secretion of a body hormone (aldosterone). They are unlikely to improve symptoms, but will make you live longer.
• Ivabradine, which can help reduce the heart rate if it is not reduced by beta-blockers.
• Digoxin regulates the heart rhythm in patients with atrial fibrillation. It is sometimes used in patients with heart failure who do not have atrial fibrillation
Angiotensin receptor / neprolysin inhibitors: These new drugs are better than ACE inhibitors. Some patients who are breathless and with a left ventricular ejection fraction of less than 40% may qualify for this treatment. It is imperative that ARNI are not taken if you are taking ACE inhibitors or ARBs.
Cardiac device therapy
These treatments have revolutionised the treatment of patients with heart failure. The suitability for CRT depends on symptoms (breathlessness), the ECG and the echocardiogram.
• Cardiac resynchronisation therapy (CRT): Cardiac resynchronisation therapy (CRT) is aimed to correct delays in electrical impulses across the heart in patients with heart failure It does so by delivering electrical impulses to various areas of the heart, usually three – the right atrium, the right ventricle and the left ventricle. CRT has been shown to improve quality of life and to make patients live longer. Importantly, it does so even in patients who take all the required medications for heart failure.
• CRT with defibrillator therapy: CRT can be combined with a cardiac defibrillator (ICD). This device detects abnormal heart rhythms (ventricular tachycardia and fibrillation) and shocks the patient out of the rhythm with an electrical discharge. Currently, around 80% of patients who are treated with CRT receive this combination (CRT-D).
• Implantable left ventricular assist device (LVAD): The LVAD is known as a ‘bridge to transplantation’ for patients who haven't responded to other treatments and are hospitalised with severe systolic heart failure. This device helps your heart pump blood and allows you to be mobile, sometimes returning home to await a heart transplant. In the UK NHS, only patients who are accepted to the heart transplant waiting list can be treated with LVADs.
• Heart transplantation: Most patients with heart failure are well controlled on drug treatment. A minority of patients, however, may need surgery to improve the pumping action of the heart. Heart transplantation is the last resort. In the UK, it is only available to the few, due to the shortage of donors.
What can I do ?
• Take your medications as prescribed. These are not only prescribed to improve your symptoms (breathelessness, fatigue) but also, to make you live longer. Some medications will not make you feel better. Other medications are designed to treat the causes of heart failure, such as a heart attack and high blood pressure.
• Keep your blood pressure in target. Your specialist will guide you as to the best blood pressure for you to keep.
• Monitor fluid retention. You should know from your doctor what your ‘dry weight’ is. Check for fluid retention by weighing yourself daily. Weigh yourself daily, preferably in the morning without clothes, after passing urine but before eating. You should suspect a worsening of heart failure if if you gain weight (1.5 kg in one day or 2.5 kg in one week). You should also check for ‘pitting oedema’ by pressing on the skin of the lower legs for 5 seconds. If the finger leaves a mark, then you have ‘pitting oedema’ (see Figure)
• Keep a record of fluid intake. This is useful if you have or are likely to develop accumulation of fluid. If so, you should keep your fluid intake to less than 2 litres per day.
• Keep an eye on salt intake: Sodium is found in most foods, but the highest concentrations are in processed foods. A low sodium diet reduces fluid accumulation.
• Be alert for new symptoms. You should seek specialist medical advice if new symptoms occur or if your symptoms worsen.
• Keep regular appointments. Once heart failure is stable, you should be assessed by a specialist at least every 6 months. More frequent appointments will be needed if symptoms change or if you need changes in medication.
• Exercise regularly. Exercise rehabilitation may be suitable for some patients with heart failure.
• Stop smoking.
• Keep up to date with immunisations: Your GP will inform you on influenza and pneumonia immunisations.
• Keep up to date with device follow-up: If you have had a CRT or an ICD implanted, ensure that you keep up your appointments in the device clinic.
Other treatments for patients with heart failure aim to improve the disease that caused heart failure in the first place. Thus, patients with a previous myocardial infarction will be treated with cholesterol-lowering drugs, such as the statins (simvastatin, pravastatin, atorvastatin); and aspirin to make blood less sticky. Patients with high blood pressure may also need to be on additional drugs.
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