Diagnosis of heart disease
If you do have a heart problem, you will find yourself seeing your general practitioner (GP) at some stage, usually when symptoms appear. A consultation with him or her, and perhaps some tests, will often give the diagnosis. You will probably be referred to a cardiologist at your local hospital. A cardiologist is a heart specialist but should not be confused with a cardiac surgeon. The cardiologist is the first person to whom you will be referred if you get diagnosed with suspected heart disease. He or she will perform a number of tests to aid in the diagnosis, and may start any combination of a number of different treatments. These are dealt with in the Family Doctor book Understanding Coronary Heart Disease. In most cases some medical treatment, such as drugs, will be enough to keep the symptoms at bay for the time being. However, the processes that cause the disease are usually ongoing or progressive, and different drugs may need to be added in increasing doses. It is usually only if these treatments reach a maximum level or fail to control the symptoms that the cardiologist will then refer you to a cardiac surgeon for an opinion about the potential benefits of surgery. Most patients with heart problems, therefore, will never get to meet a cardiac surgeon. This is a very specialised field of medicine and there may not be one in your local hospital. In this event, you will go to see the surgeon at the nearest large centre for cardiac surgery. The cardiologist and the cardiac surgeon will then discuss you and your problems, and decide whether an operation would help, or whether a different option may be better for you.
From the moment you first bring your problem to the attention of your GP (or any doctor), a series of things will happen to you in order to establish the diagnosis, as shown in the box.
HISTORY
First of all, your doctor will ask you for a full and detailed description about yourself, both in relation to this particular illness and your symptoms and in relation to other details that may seem unrelated. All this information will be written down in your medical notes, and is known as your ‘history’.
It is important for the history to paint as complete a picture as possible, because many little things that might seem unimportant to you may give clues towards your diagnosis. Details about your current problems are usually easy to give, but your past medical history (such as childhood rheumatic fever) and your family history (for example, relatives who have had heart attacks at a young age) are vitally important too.
By the time an accurate history has been taken, before a hand is even laid upon you, a very good idea about your diagnosis has usually been made.
EXAMINATION
Next, you will be carefully examined. You may find that your doctor looks at your face, neck, hands and ankles thoroughly, before turning to your chest. This may seem odd, because you have a chest problem, but it is very important, because there are many clues to the diagnosis of heart disease in these areas. He or she may do some other peculiar things when examining your chest, such as tapping with the fingers, which is known as percussion. You will always have your chest listened to with a stethoscope, both front and back. Using this, your doctor will be able to listen carefully for any heart murmurs, as well as checking for left heart failure which causes fluid on the lungs.
At this stage, after your history and examination, the diagnosis is pretty clear in the vast majority of cases. Your doctor will then decide, on the basis of his or her suspicions, which tests are needed to confirm this, and which treatment to start.
Chest X-ray
If you have a suspected heart condition, you will almost certainly have a chest X-ray taken at an early stage, although it usually provides only a limited amount of information. If you have IHD, the only findings of interest may be an enlarged heart shadow, and some fluid on the lungs (left heart failure), but you may not have either. Equally, if you have VHD, the findings may be very similar. The main importance of a chest X-ray is probably in the elimination of other, more serious disease in the chest.
Electrocardiography electrocardiogram (ECG)
Most people with heart disease will have an ECG performed. It is an electrical tracing of the heart’s activity, and gives important information about most of the conditions that affect it.
It is completely painless, and simply involves you lying down and having about ten sticky patches put on your chest, arms and legs. These are attached by wires to the ECG machine, which records the activity of the heart on a piece of special graph paper. The whole thing takes a couple of minutes.
The doctor looking after you will be interested in your ECG for two reasons: first, to see if there are any abnormalities which may confirm the diagnosis and, second, to compare it with any previous ECGs that you may have had taken, to see if there has been any change in your condition. Important information that can be obtained from the ECG is shown in the box.
Exercise test
Angina will usually first show itself when you are under stress or exertion. As the condition worsens, it may start to occur at rest. The change indicates a progressive narrowing of the coronary arteries. If you have angina, one of the first tests that you will undergo is the exercise test, or ‘stress test’. This takes the form of a continuous ECG recording while you are walking on a treadmill.
The wires are attached to you in exactly the same way as for a normal ECG, and the treadmill is started. It starts slowly, and will become a little faster and steeper every 3 minutes. The whole test consists of seven 3-minute periods, but it is not necessary to finish it. You can stop at any time, but the usual reasons are chest pain, shortness of breath or tiredness. A doctor will be watching the ECG tracing on a screen while you perform the test, and may ask you to stop because of changes that he sees, even if you feel fine.
You either ‘pass’ or ‘fail’ an exercise test. Passing means that you reach a reasonable level of exercise for your age and ability. Failing means that you develop chest pain, rhythm disturbances, low blood pressure or ECG changes noted by the doctor watching you.
Failing an exercise test is also known as having a ‘positive’ or ‘strongly positive’ result. In most cases this will mean that your cardiologist will recommend that you have another procedure called angiography performed (see later).
Echocardiography
Known as an ‘echo’ this is another painless and easy test to perform, but one that gives very valuable information about your heart. It is particularly useful in VHD, because it gives a two-dimensional moving image of your heart, and can see the chambers and valves. It is simply an ultrasound scan, similar to the ones that most women will have in pregnancy. You will be asked to lie down on a semi-upright couch, and the operator (either a cardiologist or a specialist echocardiographer) will run the probe across your chest, using a little lubricant jelly to help the contact.
The operator moves the probe from place to place to look at different parts of the heart, while watching the screen. The whole echo is recorded on a video tape, so that it can be watched later by other experts if necessary. Using this test, the valves can be measured for the degree of narrowing or leakiness. The function of the ventricles as pumps can also be observed, by watching how well they contract with each beat. Echocardiography is very useful, because it gives a quick, comfortable result and, as the tapes are kept, comparisons can be made of an individual patient over a period of time, to see whether things are worsening.
Most echocardiograms are performed as described above by moving the probe across the front of your chest. This is called a transthoracic echocardiogram (TTE). There is, however, another form of echocardiography that gives a more accurate image and is particularly useful for certain specific conditions. It is called transoesophageal echo-cardiography (TOE) and is a little more invasive than TTE. It involves swallowing a tube containing the ultrasound probe into your oesophagus (gullet) and down into your stomach. As some people can find this a bit uncomfortable, the procedure is usually performed under some light sedation. TOE is particularly useful during some heart operations, especially valve surgery, and can show both the anatomy and the result of surgery quite clearly.
Angiography
Also known as ‘angio’ or cardiac catheterisation, this is the definitive test for looking at coronary artery disease (IHD). You will be required to have angiography if there is a strong suspicion that something other than drug treatment needs to be done to your coronary arteries to make you better. This suspicion is raised if you ‘fail’ your exercise test, or sometimes if you continue to get angina after a heart attack.
Unlike the previous tests, it involves a drip being put in your arm, and you’ll be given a mild sedative to relax you, although you’ll remain conscious during the procedure. This test takes place in a special room or ‘suite’ called the ‘Cath Lab’, with a movable bed for you to lie on, and a big overhead X-ray machine. The actual procedure needs a larger drip to be placed in one of the large arteries in your arm or leg. This is usually in your groin or in front of your elbow, and is performed under local anaesthetic. Some dye is then injected down this big drip, and passes into your heart and your coronary arteries. The procedure is being filmed the whole time by the X-ray machine. By injecting dye down each of the coronary arteries in turn, it is easy to identify where the narrowings are, and how severe they are. It ends up giving a sort of ‘road-map’ of the heart. Dye can also be used to show how efficiently the heart is working as a pump, and information may also be gained about the condition of the heart valves and the size of the aorta.
The whole procedure takes about half an hour, and you can go home after a rest of about four hours. The film is then looked at by your cardiologist and, if necessary, by the cardiac surgeon.
Other tests
There are a number of other tests and investigations that are used to diagnose heart disease. Some of these are simple and common, and some of them are more complex and only used in specific circumstances. Of these, you are most likely to have blood tests at some stage. Those that may provide information, which may be significant in terms of the heart disease itself, are for cholesterol (and triglyceride) levels and cardiac enzymes.
If you are suspected of having IHD, particularly if you have a family history of it, your doctor will measure your cholesterol levels and, if they are high, you will be given advice and possibly some treatment. Failure to recognise and treat this will result in more rapid progression of the coronary artery narrowings.
Cardiac enzymes are measured if you have had an acute myocardial infarction (MI or heart attack), or even a bad attack of angina. You get very high levels in the blood if you have had a heart attack, but much lower levels with angina. They are therefore helpful in the differentiation between the two, and will guide appropriate treatment for whichever is diagnosed.
There are a number of other tests used in the diagnosis of heart disease. These include thallium, MUGA (multi-gated acquisition), and PET (positron emission tomography) scans. These are procedures that involve the use of radioactively labelled compounds or isotopes, and they are performed in a Department of Nuclear Medicine on a ‘day visit’ basis. If you are having one of these tests, you will have an injection of a tiny dose of a radioactive marker, and then you will be screened by a special machine. There is nothing dangerous or uncomfortable about either of these tests. They do not make a diagnosis of the specific disease process, but aid in giving information about the heart’s pump function, and the general state of the heart muscle.
In addition there is increasing use of cardiac MRI (magnetic resonance imaging), as well as a form of echocardiography carried out under higher work conditions, known as ‘stress echo’ or ‘dobutamine echo’ because of the drug used. More about these and other diagnostic tests can be found in other books in the Family Doctor series.
