Eamonn Brady MPSI looks at the clinical considerations in the different types of heart failure, including prevention, causes and effectiveness of therapeutic interventions
Congestive cardiac failure is generally referred to as heart failure. Heart failure occurs when the heart is not working adequately. It cannot meet the body’s need for blood because it is not pumping properly and usually occurs because the heart muscle has become too weak or stiff to work properly. It has a high mortality rate, with a 30 per cent mortality rate one year from diagnosis, and a 60-to-70 per cent five-year mortality rate. However, survival rates are improving due to better treatment regimens, with six-month mortality rate in the UK reduced from 26 per cent in 1995 to 14 per cent in 2005.
How common is heart failure?
Heart failure affects 2 per cent of the Irish population but is more common among the elderly. It affects 6-to-10 per cent of the population aged over 65. The average age of diagnosis is 76. It is the leading cause of hospital admissions in the over-65 age group, accounting for 20 per cent of hospital admissions in this age group.
Acute and chronic heart failure
Symptoms of heart failure can develop quickly, and this is known as acute heart failure. It is more common for the symptoms to develop slowly over time, which is known as chronic heart failure. Acute heart failure is usually brought on by another major complication, such as pneumonia or heart attack. Chronic heart failure is caused by long-term factors such as high blood pressure, obesity, diabetes and smoking. Coronary artery disease is the most common cause of heart failure.
Types of heart failure
There are two main types of heart failure and each has different symptoms.
❤ Heart failure due to left ventricular systolic dysfunction (LVSD): When the part of the heart that pumps the blood around the body (left ventricle) is not functioning properly.
❤ Heart failure with preserved ejection fraction (HFPEF): When the heart has difficulty filling with blood.
Causes of heart failure
There is generally not a single cause of heart failure. It is generally a result of a number of factors, including:
❤ Coronary heart disease, when the arteries supplying blood to the heart become blocked-up with fatty materials such as cholesterol (atherosclerosis). This is the most common cause of both heart attack and heart failure.
❤ High blood pressure puts extra strain on the heart and over time can lead to heart failure.
❤ Damage to the heart muscle (cardiomyopathy) can lead to heart failure. Damage can be caused by infections but also by alcohol misuse, drug abuse or sometimes as a side-effect of medication. Heart attacks can also damage the heart muscle.
❤ Heart rhythm problems, ie, atrial fibrillation.
❤ Heart valve disease, damage or problems with the valves in the heart due to infection, atherosclerosis or ageing.
❤ Anaemia (decrease in red blood cells).
❤ An overactive thyroid gland.
Prevention of heart failure
Many of the risk factors for heart failure can be managed, either by making lifestyle changes or by medication. Reducing these risk factors will also prevent other cardiovascular diseases such as stroke and heart attack.
Lowering blood pressure
When blood pressure is high, the heart has to work harder to pump blood around the body. To cope with the extra effort, the heart muscle becomes thicker over time, but eventually it becomes too stiff or weak to work properly. High BP affects up to 50 per cent of middle-aged and older people. High BP has no symptoms, so routine checks are essential, especially for those aged over 50. Medication can effectively reduce blood pressure.
Smoking also tends to make the blood thicker and slows down blood flow, increasing the risk of blood clots (thrombosis). It damages the linings of the arteries, causing them to block-up with fatty deposits (atherosclerosis).
High levels of cholesterol can cause arteries to narrow and become blocked with fatty deposits (atherosclerosis), causing heart attacks and strokes.
Other factors that will reduce the risk of heart failure include losing weight, regular exercise, eating a healthy diet, lowering alcohol levels, and reducing salt intake.
Some causes of heart failure cannot be controlled by lifestyle. These include:
Heart rhythm abnormalities (arrhythmias)
If the heart beats too fast, it may not have enough time to fill and empty properly, which causes the heart muscle to weaken. A slow heartbeat may reduce the heart output and cause symptoms of heart failure. An irregular heart rhythm increases the risk of a blood clot (thrombosis), causing a heart attack or stroke.
This is inflammation of the heart muscle and is most commonly caused by a virus. This inflammation can lead to heart failure.
Damaged heart valves
The heart contains four valves that allow blood to flow one way through the heart. A leaking valve means the heart has to work harder to deal with the extra volume of blood. A narrowed valve can obstruct blood flow and reduce the amount of blood the heart can pump. Over time, either a leaking valve or a narrowed valve can weaken the heart muscle. Heart valves can be damaged during a heart attack, and some children are born with faulty valves (congenital heart disease). Valves can be repaired with a surgical operation if the damage is detected in time.
Other heart diseases present at birth
Some babies are born with a ‘hole in the heart’, which is an abnormal connection between the left and right sides of the heart. Blood can flow from one side to the other (usually left to right), causing strain on the right side of the heart, which in turn may cause heart failure to develop.
Diagnosing heart failure
The patient’s symptoms are usually the
first indication of heart failure. Blood tests and an echocardiogram (ECG) can help confirm diagnosis.
Blood tests will not actually directly confirm heart failure. However, they can detect other factors that may be causing heart failure, such as cholesterol levels, anaemia, diabetes, thyroid problems or kidney disease.
Natriuretic peptide test
Blood can be tested for a substance called natriuretic peptide (also called BNP or NTproBNP). If the heart is damaged or overworked, it will secrete BNP into the blood. Higher levels can indicate heart failure. However, BNP can be altered by other factors, meaning it cannot be used as the only diagnostic indicator of heart failure. For example, obesity or treatment with diuretics, angiotensin-converting enzyme (ACE) inhibitors, angiotensin II in and aldosterone antagonists can reduce levels of BNP. High levels of BNP can have causes other than heart failure, including left ventricular hypertrophy, ischaemia, tachycardia, right ventricular overload, pulmonary embolism, chronic obstructive pulmonary disease, renal failure and sepsis. The level of BNP will not differentiate between heart failure due to left ventricular systolic dysfunction (LVSD) or heart failure with preserved ejection fraction (HFpEF).
An echocardiogram (ECG) is used to look in detail at the structure of the heart. A pulse of high-frequency sound waves is passed through the chest wall and produces a picture by bouncing back from the structures in the heart.
Treating heart failure
Once diagnosed, lifestyle changes such as reducing weight and stopping smoking can reduce the risk of further complications.
The aim of medication is to improve symptoms of heart failure and prevent further damage to the heart. The main combination of medicines for heart failure includes:
❤ A diuretic.
❤ An angiotension-converting enzyme
❤ A beta-blocker.
❤ An aldosterone antagonist.
❤ Sacubitril valsartan.
Diuretics result in a rapid improvement in symptoms and increased exercise tolerance in more than two-thirds of patients. Diuretics help to relieve ankle swelling and breathlessness caused by heart failure. They work by helping to remove water and salt from the kidneys in the urine. They are not recommended as monotherapy for the treatment of heart failure; it is recommended they be prescribed with an ACE inhibitor or a beta-blocker. Loop diuretics are the first choice in heart failure. Loop diuretics include furosemide and bumetanide and there is no difference in efficacy between the different types. Thiazide diuretics are less-potent diuretics and are generally only used for mild heart failure or as an add-on therapy, ie, bendroflumethiazide.
The dose of diuretic is generally started low and increased slowly until response. People who have heart failure with preserved ejection fraction should usually be offered a low-to-medium dose of loop diuretics (for example, less than 80mg furosemide per day). The dose may be reduced once the patient is started on optimal ACE inhibitor dosage. Low potassium level is a side-effect of diuretics but because they are normally taken with ACE inhibitors for heart failure, this is rarely a problem. NSAIDs should be avoided with diuretics, as they reduce their effectiveness and concomitant use can reduce kidney function.
ACE (angiotensin-converting enzyme) inhibitors block the conversion of the hormone angiotension 1 to angiotension 11. Angiotension 11 is a natural vasoconstrictor and also encourages fluid retention. Thus, ACE inhibitors work by dilating blood vessels, which makes the blood flow more easily and reduces blood pressure. This makes it easier for the heart to pump blood around the body. ACE inhibitors are recommended for mild and severe heart failure.
They decrease the rate of hospitalisations, improve symptoms and increase survival in heart failure patients. Examples of ACE inhibitors include ramipril, captopril, enalapril, lisinopril and perindopril. The most common side-effect is a dry, irritating cough. They should be started at a low dose and increased every one or two weeks until response. They can cause postural hypotension (dizziness and falls from low blood pressure) when started, so blood pressure should be monitored. Kidney function also needs to be monitored.
Angiotensin receptor blockers (ARBs)
ARBs have been shown to extend life and reduce symptoms in patients with heart failure. They work in a similar way to ACE inhibitors, by widening blood vessels and reducing blood pressure, and tend to be used as an alternative, as they do not usually cause cough. Examples include candesartan, losartan, telmisartan and valsartan. Side-effects include hypotension and high potassium levels. Measure serum sodium and potassium, and assess renal function, before and after starting an ARB and after each dose increment.
Research has shown that beta-blockers can reduce symptoms and increase survival in patients with heart failure. They are not suitable for asthmatics. They are generally used on patients with little or no fluid retention. They work by slowing heart rate and perhaps by protecting the heart from the effects of adrenaline and a related chemical, noradrenaline. Dosage should be increased slowly. The beta blockers used to treat heart failure are bisoprolol, carvedilol and nebivolol. These are the only three beta blockers licensed for the treatment of heart failure. Patients who are already taking a beta blocker for a pre-existing condition such as hypertension or angina (ie, atenolol) should be switched to a beta blocker licensed for heart failure once they are diagnosed with heart failure due to left ventricular systolic dysfunction.
Lethargy and fatigue are the most common side-effect of beta blockers. They should not be stopped suddenly, as this can cause a rebound effect with rapid worsening of symptoms. A major trial indicated that nebivolol is more effective than other beta blockers at increasing survival in the over-70s age group. However, further studies have questioned the methodology of the SENIORS trial, which indicated that nebivolol is more effective than other beta blockers in controlling heart failure. The general consensus now is that nebivolol is no more effective than bisoprolol and carvedilol in treating heart failure in the over-70s.
Mineralocorticoid receptor antagonists (MRAs)
MRAs are suitable for some people with heart failure. They work in a similar way to diuretics, but can also help heal any scarring of the heart muscle. MRAs are an option in addition to an ACE inhibitor (or ARB) and beta-blocker in patients who have heart failure with reduced ejection fraction if they continue to have symptoms of heart failure. Once the target, or maximum tolerated, dose of an MRA is reached, treatment should be monitored monthly for three months and then at least every six months, and at any time the person becomes acutely unwell.
The most widely used aldosterone antagonist is spironolactone. It is a potassium-sparing diuretic. Regular blood screening to monitor potassium level is important, as it raises potassium. Raised potassium levels are exacerbated when taken with ACE inhibitors or angiotension receptor inhibitors. In a two-year review, it reduced mortality in patients with severe heart failure from 46-to-35 per cent when used as ‘add-on’ therapy to existing diuretic, ACE inhibitor and beta-blocker therapy. Side-effects of spironolactone include gynaecomastia in men and breast tenderness and increased hair growth in women.
Eplerenone, as compared with placebo, reduced both the risk of death and the risk of hospitalisation among patients with systolic heart failure and mild symptoms. The most severe side-effect of spironolactone, hyperkalemia, is also observed with eplerenone. While eplerenone is more selective, with the potential for fewer side-effects, its overall efficacy has not been proven to be superior to that of spironolactone in clinical trials. Eplerenone can cause hyperkalaemia, sleeping difficulties, dizziness and headaches.
Digoxin, related to a medicine derived from the foxglove plant, increases the strength of heart muscle contractions and can also slow down heart rate. It is recommended for people who have symptoms despite treatment with ACE inhibitors, ARBs, beta-blockers and diuretics. It is used earlier in people who have both heart failure and atrial fibrillation. Potassium levels must be monitored regularly to avoid toxicity due to hypokalaemia. This is especially important when taken with diuretics which reduce potassium levels.
In patients with heart failure in sinus rhythm, anticoagulants should be considered for those with a history of thromboembolism, left ventricular aneurysm, or intracardiac thrombus. Warfarin is the most commonly used anticoagulant, and requires careful monitoring.
Antiplatelet medicine, for example aspirin 75mg, should be prescribed for patients with the combination of heart failure and atherosclerotic arterial disease (including coronary heart disease). Aspirin is not usually taken with warfarin.
Calcium Channel blockers
Amlodipine is a treatment option for co-existing hypertension and/or angina in patients with heart failure, but verapamil, diltiazem or short-acting dihydropyridine agents should be avoided.
More specialised treatments
Ivabradine is a useful alternative to beta blockers in patients who can’t tolerate beta blockers. It can be used in addition to beta blockers if beta blockers are not controlling heart rate sufficiently.
Ivabradine is recommended in patients:
❤ With New York Heart Association (NYHA) class II to IV stable chronic heart failure with systolic dysfunction.
❤ Who are in sinus rhythm with a heart rate of 75 beats per minute (bpm) or more.
❤ In combination with standard therapy, including beta-blocker therapy, angiotensin-converting enzyme (ACE) inhibitors and aldosterone antagonists, or when beta‑blocker therapy is contraindicated or not tolerated.
❤ With a left ventricular ejection fraction of 35 per cent or less.
Ivabradine should only be initiated after a stabilisation period of four weeks on optimised standard therapy with ACE inhibitors, beta‑blockers and aldosterone antagonists. Ivabradine should be initiated and monitored by a heart failure specialist.
Sacubitril valsartan (Entresto) was approved by the European Medicines Agency in 2016. It is licensed for symptomatic chronic heart failure with reduced ejection fraction, only in people:
❤ With NYHA) class II to IV symptoms.
❤ With a left ventricular ejection fraction of 35 per cent or less.
❤ Who are already taking a stable dose of angiotensin‑converting enzyme (ACE) inhibitors or ARBs.
Sacubitril blocks the breakdown of natriuretic peptides produced in the body. Natriuretic peptides cause sodium and water to pass into the urine, thereby reducing the strain on the heart. They also reduce blood pressure and protect the heart from developing fibrosis (scar tissues) that occurs in heart failure. Valsartan is an angiotensin receptor blocker, so works by widening blood vessels and reducing blood pressure.
Entresto is taken twice a day. The recommended starting dose is one tablet of Entresto 49mg/51mg twice a day and the dose is then doubled after two-to-four weeks to 97mg/103mg twice a day. The most common side-effects of sacubitril valsartan are hypotension, hyperkalemia and renal problems.
Treatment with sacubitril valsartan should be initiated and monitored by a heart failure specialist.
Medication for heart failure with HFPEF
Approximately half of patients with heart failure in the community have preserved left ventricular ejection fraction (HFPEF). Traditionally, pharmacological research has focused on heart failure with left ventricular systolic dysfunction (LVSD) and found several drugs to be beneficial, including ACE inhibitors, beta-blockers and aldosterone antagonists. However, studies of treatment in patients with preserved left ventricular ejection fraction have found no significant benefit of these drugs. There is some limited evidence that suggests potential benefit of both beta-blockers and ACE inhibitors for HFPEF. However, more studies are needed to prove the benefit of these drugs in HFPEF; this means that many patients presenting to pharmacies for these drugs to treat heart failure may not be getting any benefit from them.
Non-drug treatment options
Medication is the mainstay of treatment. However in certain situations, the patient may need other treatment options. This includes pacemakers in situations where the heart beats too slowly. Cardiac resynchronisation therapy may be required when the ventricles don’t contract correctly and involves inserting a small pacemaker. Implantable cardioverter defibrillators are used when the ventricles contract too fast and this device keeps the rhythm regular. Surgery may be required, especially in situations where the heart valves are damaged. If heart failure is related to coronary heart disease, a coronary angioplasty or a coronary artery bypass graft (CABG) may be required to help get the blood flowing to coronary arteries
Signs that indicate the condition is getting worse include:
❤ Shortness of breath that is not related to usual exercise or activity.
❤ Increased swelling of the legs or ankles.
❤ Swelling or pain in the abdomen.
❤ Trouble sleeping, or waking up short of breath.
❤ Dry, hacking cough.
❤ Feeling more and more tired, or feeling tired all the time.
What happens towards the end?
As heart failure gets more severe, a person may become more and more immobile. The breathlessness can get worse and become extremely distressing. Sometimes, opioid analgesics may need to be prescribed to ease the feeling of breathlessness. Some patients find that pain becomes more of a problem as their heart failure worsens.
Opioids can also help relieve pain.
References on request
Symptoms of heart failure
- Shortness of breath, especially with activity
- Shortness of breath when lying flat
- Swollen feet and ankles
- Loss of appetite and abdominal swelling
- Dizziness or near fainting episodes
- Irritable cough, sometimes producing frothy sputum
- Sudden severe breathlessness waking one from sleep – this requires urgent attention
- Confusion or difficulties in concentrating
Avoiding certain medications
Heart failure patients should avoid non-steroidal anti-inflammatory drugs (negative effect on kidney function leading to fluid retention), tricyclic antidepressants (cardiotoxic), lithium (risk of toxicity with sodium depletion), and corticosteroids (fluid retention, hypertension).