Mammography is a specialty that requires us to be advocates to the public for all manner of health related issues. Breast imaging has a personal and emotional component to it. Our patients trust us, place their faith in us and rely on us to be knowledgeable in many areas of health care.
On the whole we deal with middle aged female patients. Recently it has been shown in clinical trials that this demographic is a dire risk of heart attack and other cardiac disorders simply by not knowing they are at risk. We have a responsibility, not to diagnose, not to treat, but to be able to give cogent, informed advice when asked because she may never ask anyone else.
This month begins a three part series on the hearts of our patients. Although this seems like a topic that does not relate to our specialty, all knowledge is power. Accept the knowledge and use it to edify your life.
PART TWO: HEART FAILURE
OBJECTIVES:
Heart failure sounds quite alarming. But it only means that the heart is not working as well as it used to, not that it has failed completely. Heart failure is usually a chronic (long-term) condition, with no complete cure. Treatment aims to reduce symptoms and prolong life.
People with heart failure are more prone to potentially dangerous conditions such as:
abnormal heart rhythms (arrhythmias)
stroke (damage to the brain caused by lack of blood supply)
heart attack
blood clots on the lung, in the leg veins and in the arteries of the arms and legs (called thromboembolism)
liver problems
depression (a third of people with heart failure develop severe depression)
What causes heart failure?
A number of conditions can cause heart failure to develop. Some examples are listed below.
Coronary Heart Disease (Heart attack and/or Angina). The most common reason for heart failure. It causes damage to the heart muscle, preventing it from being able to pump enough blood around the body.
High blood pressure (hypertension). This puts extra strain on the heart and can lead to heart failure over time.
Heart valve abnormalities (either narrowed or weakened valves). These abnormalities can develop after rheumatic fever in childhood. They can be present at birth, or they may be caused by a heart attack. In developing countries this is the most common cause of heart failure.
Heart rhythm abnormalities. A fast and/or irregular heartbeat does not allow the heart to fill with enough blood before it pumps it around the body.
Congenital heart disease. This is a heart condition that is present at birth. For example, a hole in the heart's septum (the division between the left and right sides) can overload the heart with blood, causing heart failure to develop.
Anemia or an overactive thyroid gland can also cause heart failure by making the heart beat too fast and work too hard.
Symptoms
One of the main symptoms of heart failure is tiredness and a lack of energy. This is because of poor blood supply to the muscles. Other symptoms depend on which side of your heart is most affected.
Left heart failure affects the side of your heart that pumps blood around your body. It commonly develops after a heart attack. Symptoms include breathlessness when exercising and/or when lying flat, severe breathlessness in the early hours, fatigue and a cough with frothy spit.
Right heart failure affects the side of the heart that pumps blood to the lungs. It often happens as a result of left heart failure, but it can also be caused certain chronic lung problems, such as chronic bronchitis. Right heart failure results in a build up of fluid in the legs that can extend over the lower back and inside the abdomen (where it is called ascites). The liver can become enlarged and there may be nausea and swollen veins in the neck. The extra fluid may cause weight gain, although severe chronic heart failure sometimes causes wasting.
Figure 1 CARDIAC/PULMARY CIRCULATION
Diagnosis
A physical examination and a review of the medical history will help the practitioner diagnose heart failure.
Diagnostic tests include:
A blood and urine test, to check things such as blood count, liver function and other markers of heart failure - B-type natriuretic peptide (BNP) is a common marker test which indicates left heart failure
An electrocardiogram (ECG), which traces the electrical activity in a heart
An echocardiogram (heart ultrasound scan), to show the pumping action of the heart and valves
A chest X-ray, to show the size of the heart and to check for fluid on the lungs
A range of medicines can be used to relieve the symptoms of heart failure and slow down any worsening of the condition. Any underlying cause will be treated first (for example, drug treatment given to lower blood pressure).
The various types of drugs used to treat heart failure work in different ways.
ACE inhibitors
These drugs reduce the production of hormones which constrict blood vessels. This makes the walls of the blood vessels relax, which reduces pressure and makes it easier for blood to circulate. Overall, they improve the performance of the heart, reduce heart failure symptoms and prolong life. Side-effects can include a persistent dry cough, low blood pressure and faintness.
Angiotensin II antagonists
These act directly on the blood vessel wall to block the effects of the hormones which constrict them. Their action is therefore similar to those of the ACE inhibitors but they tend not to cause a dry cough. They are used if ACE inhibitors cause too many side-effects.
Beta-blockers
Beta-blockers are commonly used for treating high blood pressure. They also steady the heartbeat and make the heart more able to cope with exercise. In the past they were thought to be unsuitable for people with heart failure. However, studies have shown that specific beta blockers can actually help in some heart failure patients. They aren't suitable for people who have asthma.
Loop diuretics
These increase the production of urine, which helps to remove excess fluid from the body. This reduces leg swelling and removes fluid from the lungs, and can improve symptoms such as breathlessness. There are some side-effects. Diuretics can upset the balance of salts in the body (especially potassium), leading to muscle weakness, fatigue and abnormal heart rhythms. Other drugs or potassium supplements may help to counter this.
Spironolactone
This is a type of diuretic which works by interfering with the action of the hormone aldosterone. It is sometimes used if other medicines aren't helping to control the heart failure.
Digoxin
This works to slow the heartbeat and improve the heart muscle's pumping ability. It is used if symptoms aren't adequately controlled by ACE inhibitors and other drugs. Side-effects can include a loss of appetite and nausea.
Hydralazine and nitrates
ACE inhibitors or angiotensin II antagonists do not always help to control heart failure symptoms and are sometimes not tolerated. In these situations, hydralazine and nitrates, which relax the walls of blood vessels, have been shown to be useful.
Other treatments
Anticoagulants, e.g. warfarin
Blood clots are more likely to form in the heart chambers of people with heart failure and arrhythmias. These can be carried in the circulation and may block narrow vessels, preventing blood from reaching some tissue. If this happens in the brain it's called a stroke.
Anticoagulants are used to thin the blood, making blood clots less likely. Taking warfarin requires careful monitoring with regular blood tests. These drugs must be moderated before and after any interventional procedure. Thinning the blood too much, for example, can mean that an injury causes bleeding that is difficult to control.
Transplantation
For some people who have severe heart failure and a life expectancy of less than six months, a heart transplant may be an option. This can be a very successful procedure, although complications such as rejection of the donor heart can occur. It isn't suitable for all patients, and is limited by the amount of donor hearts available.
The best method of controlling heart failure is of course head it off at the pass! To greatly reduce the incidence of heart failure it is vital to tackle the underlying causes. A heart-healthy lifestyle can reduce the risk of heart failure by reducing the risk of coronary artery disease and hypertension. This means not smoking, being physically active most days and eating a balanced diet. Sticking to moderate drinking and keeping a check on the blood pressure is also sensible. Most cardiac professionals also recommend you make these changes if you already have heart failure, to help prevent it getting worse.
We, as mammographers, largely deal with female patients over the age of 50 years. It has been widely acknowledged that this group of patients is at risk of serious heart problems simply by not being aware they are at risk. Power is knowledge, pass it on!
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