Heart failure occurs when the heart can no longer pump enough blood to meet the demands of the body. Failure may affect either or both pumping chambers, or may be limited to filling problems. The condition may occur suddenly, but usually develops slowly. The commonest cause of heart failure is Coronary Artery disease; the risk factors for CAD thus apply to heart failure as well. Managing these risk factors can significantly affect the course of heart failure. Treatment can be effective, and usually is a combination of medication and lifestyle changes. Any underlying medical conditions such as diabetes must also be treated. Surgery can be effective for some underlying conditions, such as valve disease. As a last resort, heart transplantation may be considered. Managing heart failure is a long term process, but lifespan can be extended and quality of life improved.
Heart failure means that the heart cannot pump enough blood to meet the needs of the body’s organs and tissues. It is sometimes called “Congestive Cardiac Failure” or CCF, because the failure results in a build-up of fluids in the body, called tissue congestion. This typically affects the lungs, abdomen, liver and lower legs.
The heart has two main pumping chambers or ventricles, which must relax to fill with blood, then contract to pump the blood out to where it is needed. The right ventricle pumps used blood to the lungs to collect oxygen, whilst the left (main) ventricle pumps out oxygen-rich blood arriving from the lungs to the whole body. A normal left ventricle pumps out ± 60% of the blood it receives: this figure is called the Ejection Fraction (EF). When the EF drops to 30-40%, heart failure exists.
Heart failure can affect the left ventricle only, right ventricle only, or both. Most often, the left side is affected, and this can in turn lead to right heart failure. In addition, the ventricles may become stiffened, and thus not relax enough to fill properly – this filling problem is called Diastolic failure – whereas poor pumping function is called Systolic failure. Failure can thus be classified according to which part/s of the heart are affected, and whether it is diastolic or systolic, and the extent of failure can be quantified in terms of the EF.
Diagram illustrating normal heart + heart failure
Heart failure typically occurs slowly, but may happen very suddenly under certain conditions – see under Causes and Associated risk factors.
As heart failure develops, the body tries to increase the pumping efficiency by increasing the heart rate, and by retaining sodium (salt) and water. These compensatory steps may initially be of benefit, but eventually worsen the whole situation by contributing to congestion and reducing the percentage of blood pumped with each heartbeat (ejection fraction).
Causes & associated risk factors
In a minority of patients, no cause can be found, and this is called Idiopathic failure.
In the vast majority, though, heart failure is associated with an underlying problem, the commonest of which is Coronary Artery Disease (CHD). It follows then, that because Heart Failure is often the end result of CHD, all the risk factors associated with CHD will also apply to Heart Failure. The most common causes of, and associated risk factors for heart failure are:
Coronary Artery Disease – blockages of arteries in the heart with decreased oxygen supply to the heart muscle. These blockages are due mostly to fatty cholesterol plaques. If the plaque is eroded and a clot forms, this may totally block the artery, and cause death of heart muscle (a heart attack), which can very quickly impair the heart’s ability to pump efficiently.
- Hypertensive heart disease – damage to the heart muscle from longstanding high blood pressure. The heart muscle may at first become thicker to try to work better, but this may cause increased stiffness and poor filling. Eventually, the heart may enlarge, and become too weak to pump effectively.
- Valvular heart disease – heart valve problems putting strain on the heart muscle. A narrowed valve needs the heart to pump harder to get blood through the narrowing, whilst a leaking valve allows blood to flow back into the heart, causing constant overloading, and eventual enlargement.
- Cardiomyopathy – a diseased heart muscle, often from an unknown cause, but sometimes associated with a viral infection.
- Arrhythmia-induced heart disease – abnormal heart rhythm, leading to heart muscle damage. If the heart rate is too fast, it creates extra work for the heart. A very slow rate can prevent the heart from adequately perfusing the body, and can by itself lead to pump failure.
- Congenital heart disease – inborn abnormalities of the heart. These are usually structural abnormalities of the chambers and valves, which therefore cannot function correctly, and rapidly cause heart failure. Some genetic defects increase the risk of certain types of heart disease, and this can in turn lead to failure.
- Toxin-induced heart disease – exposure of the heart to various toxins such as prolonged alcohol abuse
- Constrictive pericarditis – a disease of the sac surrounding the heart
- Diabetes – this increases the risk of hypertension and CAD, and is often associated with obesity and raised blood cholesterol levels.
- Kidney disorders - some are can cause high blood pressure and fluid retention.
- Other disorders – such as hyper- or hypothyroidism, emphysema, severe anaemia can also contribute to heart failure.
Symptoms and signs
At first, symptoms of heart failure may be absent although your internal pump is failing. Then gradually symptoms do occur because:
- The body is not getting enough oxygen and nutrients.
- Blood backs up into the lungs and body.
- Compensatory responses occur, including tightening of the blood vessels and retaining of fluid in the body tissues, called oedema.
The earliest and most common symptoms of heart failure are lung or systemic congestion, which causes the following symptoms:
- Shortness of breath while lying down that is relieved by sitting or standing up. A person may wake up coughing and/or wheezing, with a rapid heart rate, and the feeling of being suffocated. Difficult breathing and shortness of breath may occur during routine activities or exercise that did not previously cause breathing problems.
- Dry, hacking cough, especially when lying down
- Fluid build-up (oedema), especially in the legs, ankles, and feet
- Dizziness, fainting, fatigue, or weakness
- Rapid weight gain (due to fluid build-up)
- Increased urination at night
- Nausea, abdominal swelling, tenderness, or pain may result from fluid build-up in the abdomen
- Swollen or distended neck veins
How is it diagnosed?
Diagnosis always starts with a detailed medical history, in which the doctor asks about symptoms such as shortness of breath, coughing, rapid weight gain (due to fluid retention), recent illness/heart attacks etc. This is followed by a careful examination, which includes
- Checking neck veins for distension
- Checking the abdomen and legs for signs of fluid retention
- Listening to the lungs for signs of fluid overload
- Listening to the heart sounds for a characteristic sound heard in heart failure, evidence of any valve lesions, and abnormal rhythms.
Specific tests are then done to verify the heart failure diagnosis, measure its extent, and determine whether there are underlying, potentially reversible causes. These tests may include:
- Blood tests – to determine anaemia; kidney, liver and thyroid function; blood sugar measurements.
- ECG – to detect any rhythm abnormalities
- Chest x-ray – gives valuable information on the size of the heart, the presence of other contributing lung disease, and the amount of congestion(fluid build-up) in the lungs.
- Echocardiogram - this test uses sound waves to produce a video image of the heart. This gives information about valve structure and function, the contractility of the heart muscle, and can be used to compute the Ejection Fraction.
- Coronary angiogram – this shows any narrowing or blockages in the heart’s arteries, and shows the contractility of the left (main) ventricle.
- Nuclear scan – this test uses a small amount of radioactive material to actually measure the EF.
How is it treated?
Heart failure is usually a chronic disease needing lifelong treatment. In some patients, however, congestive heart failure can be improved and even cured by treating the underlying disease process. An example of this would be valve replacement surgery in a failing heart with a valve abnormality.
However, in many other patients the underlying problem cannot be solved. The goal of treatment is therefore to prevent further damage to the heart and to improve its pumping ability. This is usually achieved with medication and lifestyle modification, but surgery may be considered as another treatment option.
Angiotensin-converting enzyme (ACE) inhibitors
These the only drugs clearly proven in various medical trials to help people with the disease feel better and live longer. The drugs include captopril, enalapril and ramipril.
ACE inhibitors help the failing heart by relaxing the arteries in the body, thus lowering blood pressure. This allows blood to flow from your heart more easily, decreasing the workload on the heart. They also decrease sodium and water retention.
ACE inhibitors cause an irritating cough in about 20% of people taking them. But it may be best to put up with the cough, if you can, to gain the medications' benefits. Patients with this side effect may be switched to an Angiotensin Receptor Blocker instead.
Often called "water tablets", diuretics make you urinate more frequently and prevent fluid from collecting in your lungs and elsewhere in your body. An example of a commonly prescribed diuretic is furosemide. Some diuretics cause Potassium and Magnesium loss, so these electrolytes must be monitored and supplements given if necessary.
Digoxin, also called digitalis, slows the heart rate and increases the strength of heart muscle contractions. While digoxin doesn't improve overall survival rates, it reduces heart failure symptoms and improves your ability to function with the condition.
Beta blockers approved for the treatment of congestive heart failure are carvedilol, metoprolol and bisoprolol, although carvedilol appears to be the drug of choice. These agents can stabilise some abnormal hear rhythms, and reduce the risk of death from progressive pump failure as well as the risk of sudden death.
Angiotensin II antagonists
Angiotensin II (AT-II) antagonists (losartan, valsartan) work similarly to ACE inhibitors but don't cause a persistent cough. Recent trials suggest that these agents are of similar efficacy as ACE inhibitors in the treatment of heart failure, but in general there use is limited to those intolerant of ACE inhibitors.
2. Life-style changes
The following life-style changes are important in controlling the symptoms of heart failure and may play a role in preventing disease progression:
Smoking makes the heart beat faster, reduces the amount of available oxygen to your body, damages blood vessels and causes lung disease. All of these factors individually can contribute to heart failure: when they occur together, the effect can be disastrous.
Limit intake of fats and cholesterol
This is easily achieved by following a prudent diet. Advice from a dietician may be necessary.
Restriction of salt intake
Salt, but more specifically the sodium contained in it, causes you to retain fluids. You also need to be careful when using salt substitutes.
Limiting fluid intake
If you have congestive heart failure your body will retain excess fluid. In order to minimise fluid build up and reduce the amount of diuretics you need, it is important to restrict your fluid intake to less than 2 litres per day. Weigh yourself daily to monitor any sudden fluid retention.
Limiting alcohol intake
If it is thought your heart failure is due to excess alcohol intake, it is very important to abstain totally from all alcohol. Continued use will lead to worsening heart failure. Patients with heart failure from other causes should limit their alcohol use to one or two units per day.
You should weigh yourself every morning. Rapid weight increase of 1 or 2 kg may indicate excessive fluid retention. Contact your doctor if this happens, because your medication may need to be changed. Apart from monitoring fluid retention, aim at achieving the correct body weight for your height.
Exercise was once contra-indicated in people with heart failure, but studies have shown that moderate exercise helps your heart pump more efficiently and reduces the demands on your heart muscle. Before you start exercising, talk to your doctor about the best type of exercise for you and warning signs that you've done too much and should stop.
Learning stress management techniques may be of help, but a simple and very effective means is moderate daily exercise, such as brisk walking.
3. Surgical procedures
For patients with valve problems or CAD, surgery may completely reverse the condition if done in time. The underlying conditions and risk factors contributing to the heart failure must also be attended to, e.g. hypertension, cholesterol or diabetes which may have contributed to the development of CAD in the first place. For other patients, surgical procedures are largely still being researched, and some of these include :
Implantable cardioverter-defibrillator (ICD’s)
This implantable device monitors the heart rhythm, and if an abnormality is detected, delivers a small shock to correct it.
These surgically implanted devices send impulses to the heart muscle, causing contraction. Setting can vary e.g. to keep the heart at a fixed rate, or only step in when the patient’s heart rate drops below a certain speed.
Some patients have a Dual Chamber pacemaker: this type of pacemaker sends impulses to both ventricles, to ensure that they beat in the most co-ordinated way. A third type is a combined pacemaker/defibrillator, which can act as a normal pacemaker, but can also sense the presence of a potentially life-threatening rhythm disturbance, and then deliver a shock to correct it.
These temporary assist devices are used to tide a patient over whilst awaiting other surgery, e.g. a transplant.
This procedure is no longer experimental, but is done as a last resort. There is always a shortage of suitable donor hearts, and the post-operative management (especially rejection) remains a problem.
"Heart reduction" surgery
As the left ventricle becomes weaker, it enlarges further. This compromises its pumping ability. A procedure called partial left ventriculectomy, or heart reduction surgery, can sometimes be performed. This involves removing a portion of your enlarged heart muscle and "remodelling" your heart to its near-normal size and shape. In theory, this should help your heart pump more efficiently. In practice, this procedure as been found to be not very effective, and has largely been abandoned.
In the "wrap-around" procedure, called cardiomyoplasty, a piece of back muscle is removed and wrapped around your heart. It is then stimulated electrically to contract rhythmically with your weakened heart muscle. Again, what role, if any, this procedure may have in treatment is not yet known.
Researchers are exploring the possibility of transplanting genetically manipulated pig hearts into humans with congestive heart failure. Clinical trials could begin in the three to five years in the United States.
What is the outcome?
The outlook depends much on the underlying cause and its severity. If reversible causes, e.g. a faulty heart valve, are corrected in time, the process may be halted, with an excellent outcome.
For most patients, though, established heart failure is a lifelong condition, requiring lifelong treatment. With appropriate management, heart failure can be kept under control for a long time, and deterioration in function stopped.
Long-term complications of heart failure are generally due to:
- Chronic fluid build-up, which may involve:
- Lung congestion, ranging from mild to severe, with associated shortness of breath
- Fluid build-up in the abdomen and liver, which can lead to liver problems or failure
- Breakdown of skin (ulcers), especially in the legs, due to ongoing fluid build-up (oedema)
- Cardiac arrhythmia (an abnormal heart rhythm) due to a disturbance in the electrical conducting system of the heart
- Stroke, when the increased stasis of blood in the failing heart causes a blood clot in the heart, and this travels to the brain
- Organ failure, such as kidney failure, due to decreased blood and oxygen supply to the body
- Death related to the inability of the failing heart to provide the vital (life sustaining) organs with oxygenated blood
The best way to prevent congestive heart failure is to adopt a healthy lifestyle that protects your coronary arteries against atherosclerosis (build-up of cholesterol, and narrowing and hardening of the arteries). It is also important to control medical conditions such as high blood pressure and diabetes.
Atherosclerosis, the heart's blood vessels (coronary artery disease) is a leading cause of congestive heart failure, often after a heart attack.
To reduce your risk of developing atherosclerosis:
- Don't smoke. If you do smoke, quit. Smoking greatly increases your heart disease risk.
- Watch your cholesterol level. If it is over 200 mg/dl (5.17 mmol/L), follow your doctor's advice for lowering it. A low-cholesterol diet, exercise and quitting smoking will help keep your cholesterol low.
- Keep your blood pressure low. If your blood pressure is over 140/90 mm Hg, you run a higher risk of heart disease. Exercising, limiting alcohol intake and controlling stress will help keep your blood pressure in the healthy range.
- Exercise regularly. Apart from the benefits mentioned above, it will help control your weight and your stress levels, all of which will help keep your heart healthy.
- Control diabetes by taking your medications as directed.
When to see a doctor
Seek care immediately for symptoms of sudden heart failure:
- Severe shortness of breath (trouble breathing, even when resting)
- A sudden episode of prolonged, irregular heartbeat with dizziness, nausea, or fainting
- Foamy, pink mucus with coughing
- A sense of impending doom related to the heart or lungs not functioning well
Call your doctor soon if you have symptoms of heart failure, which include:
- Difficulty breathing during routine activities or exercise that did not previously cause problems
- Shortness of breath when you lie down
- Waking up at night short of breath or feeling as if you are suffocating
- Dry, hacking cough, especially when you lie down
- Rapid weight gain (1,3 to 1,8 kg or more in just a few days; unrelated to diet)
- Skin sores developing as a result of fluid accumulation in the body (especially common in the legs)
Reviewed by Dr AG Hall, July 2007.