An ECG is a recording of your heart's electrical activity. Electrode patches are attached to your skin to measure the electrical impulses given off by your heart. The result is a trace that can be read by a doctor. It can give information of previous heart attacks or problems with the heart rhythm.

Ambulatory ECG - this can be performed with a Holter monitor which monitors your heart for rhythm abnormalities during normal activity for an uninterrupted 24-hour period. During the test, electrodes attached to your chest are connected to a portable recorder - about the size of a paperback book - that's attached to your belt or hung from a shoulder strap.

Another form of ambulatory ECG test is an Event recorder which covers 1-2 weeks. You wear a monitor (much smaller than a Holter monitor) and if you have any symptoms, such as dizziness, you press a button on a recording device which saves the recording of your heart rhythm made in the minutes leading up to and during your symptoms. Because you can wear this for a longer period of time it has a higher rate of catching your abnormal rhythm.

An ECG done when you are resting may be normal even when you have cardiovascular disease. During an exercise ECG the heart is made to work harder so that if there is any narrowing of the blood vessels resulting in poor blood supply it is more likely to be picked up on the tracing as your heart goes faster. For this test you have to work harder which involves walking on a treadmill while your heart is monitored. The treadmill gets faster with time but you can stop at anytime. This test is supervised and interpreted by a doctor as you go. This test is used to see if you have any evidence of cardiovascular disease and can give the doctor some idea as to how severe it might be so as to direct further tests and possible treatment.

Cardiology blood tests help doctors check for heart disease, monitor risk factors, and assess how well the heart is working. Some tests check for damage right now (like troponin), while others check your long-term risks (like cholesterol and blood sugar) or stress on the heart (like BNP).

Echocardiography (or cardiac ultrasound) is a test that uses high frequency sound waves to generate pictures of your heart. During the test, you generally lie on your back, gel is applied to your skin and a technician then moves the small, plastic transducer over your chest. The test is painless and can take from 10 minutes to an hour.

The machine then develops images of your heart which are seen on a monitor. This is referred to as an echocardiogram.

Echocardiography can help in the diagnosis of many heart problems including cardiovascular disease, previous heart attacks, valve disorders, weakened heart muscle, holes between heart chambers, fluid around the heart (pericardial effusion).

If doctors are looking for evidence of coronary artery disease, they may perform variations of this test which include:

• Exercise echocardiography - compares how your heart works when stressed by exercise versus when it is at rest. The ultrasound is conducted before you exercise and immediately after you stop. Either a stationary bicycle or standard treadmill is used.
• Dobutamine stress echocardiography - if you’re unable to exercise for the above test, you might be given medication to simulate the effects of exercise. During this test, an echocardiogram initially is performed when you’re at rest. Then dobutamine is given to you via a needle into a vein in your arm. Its effect is to make your heart work harder and faster just like with exercise. After it has taken effect, the echocardiogram is repeated. The effect wears off very quickly.

This test is performed by a cardiologist in a sterile catheter laboratory. The procedure will be explained to you before being requested to sign the legal consent form which will be co-signed by your cardiologist.

Most people will need to have routine blood tests and sometimes a chest X-ray (if no recent ones) before the procedure. The cardiologist may request other tests that may require separate appointments and are usually planned the day before or the day of the procedure.

You will be asked not to eat after midnight the evening before the procedure, but you may still drink water. You will be advised regarding your medications if you take any.

You are not given a general anaesthetic but will have some medication to relax you. Local anaesthetic is put into an area of skin on your wrist (or the side of your groin if access from the wrist is unsuccessful). A needle and then tube are fed into an artery and advanced through the blood vessels to the heart. Passing a catheter through the blood vessels is a painless procedure. Dye is then injected so that the heart and its blood vessels can be seen on X-ray. X-rays and measurements are then taken giving the doctors information about the state of your heart and the exact nature of any narrowed blood vessels. This allows them to plan the best form of treatment to prevent heart attacks and control any symptoms you may have. Your cardiologist may decide to perform an angioplasty (unblocking of narrowed coronary arteries) during the same procedure.

After the procedure your arm will be rested on a sling for some time (if the procedure was done through the wrist) or you will have to lie flat (without bending your legs) while the groin sheath is in place. After the groin sheath is removed, you must lie flat for a period of time to prevent bleeding. Once bleeding is secured you will mobilise normally.

This refers to narrowing of the arteries that supply blood to the heart muscle, usually due to atherosclerosis (plaque build-up). Narrowed arteries are unable to keep up with the demand needed to supply the heart muscle with blood, which can cause damage to the muscle if prolonged.

The most common symptom of this problem is chest pain that occurs when you exert yourself (angina). Typical angina chest pain is a heavy sensation in your chest associated with shortness of breath. It sometimes radiates to your arms and can make you feel like being sick, dizzy or sweaty.

Treatment consists of medication to protect the heart and its blood vessels. You will be given advice on diet changes that can protect the heart as well as stop smoking programmes. Depending on test results you may have procedures offered to surgically correct the narrowed blood vessels.

Heart failure refers to the heart failing to pump efficiently. There are many diseases that cause this including cardiovascular disease, high blood pressure, viral infections, alcohol, and diseases affecting the valves of the heart. When the heart is inefficient a number of symptoms occur depending on the cause and severity of the condition. The main symptoms are tiredness, breathlessness on exertion or lying flat, and ankle swelling. Doctors often refer to oedema, which means fluid retention usually in your feet or lungs as a result of the heart not pumping efficiently.

Tests looking for possible causes of heart failure include: Chest x-ray, Electrocardiogram (ECG), Echocardiogram (Cardiac ultrasound), Angiogram.

You are likely to be given several medications over time, started and monitored by your cardiologist and GP. These include medication to control the amount of fluid that builds up (diuretics), medication to protect your heart and slow it down as well as to thin your blood. You will often be referred to a dietitian or given advice about restricting the amount of fluid and salt you take as this can contribute to symptoms.

Heart rhythm refers to the electrical source that is driving the heart rate and whether or not it is regular or irregular. Heart rhythm can be affected by a number of conditions.

Some common terms

• Sinus rhythm is the normal rhythm
• Arrhythmia means abnormal rhythm
• Fibrillation means irregular rhythm or quivering of one part of the heart
• Bradycardia means slow heart rate
• Tachycardia means fast heart rate
• Paroxysmal means the arrhythmia comes and goes

Tachycardia

The most common form of this is atrial fibrillation. This is where the heart rhythm is irregular and often too fast. Symptoms include fatigue, palpitations (where you are aware of your heart racing or

pounding), dizziness and breathlessness.

Other tachycardias include supraventricular tachycardia (SVT) or ventricular tachycardia (VT). These have similar symptoms as atrial fibrillation but can also cause you to lose consciousness (faint).

Bradycardia

The most common form of this is called heart block. This is because messages from the electrical generator of the heart don't get through efficiently to the rest of the heart and hence it goes very slowly or can pause. Symptoms of the heart going too slowly include feeling tired, breathless or fainting.

Tests

Tests to diagnose what sort of arrhythmia you have include an electrocardiogram (ECG) and an ambulatory ECG (Holter monitor or Event recorder).

Treatment

Most treatments for tachycardias consist of medication to stop the abnormal rhythm or make it slower if and when it occurs. Atrial fibrillation, if you have other problems, can increase your risk of stroke so blood-thinning medication is often used as well.

If you have bradycardia, you may be referred to the surgeons for a pacemaker. This is a small operation where a battery powered device is placed under the skin with wires that lead to your heart and provide it with electrical stimulation to prevent it from going too slowly. You can't feel it doing this but will be aware of a small flat lump under your skin just below your collar bone.

Your heart consists of four chambers that receive and send blood to the lungs and body.

Disorders affecting valves can either cause stenosis (a narrowing) or regurgitation (leakage after the valve has closed). Depending on what valve is involved and how severe the damage is it may result in symptoms of heart failure, as it makes the heart pump inefficiently.

Suspicion of a heart valve problem is usually picked up by your doctor when they listen to your heart and hear a murmur. A murmur is heard with the stethoscope and is turbulence of blood flow that occurs through a narrowed or leaky valve. Not all heart murmurs mean serious problems but are best investigated further.

The echocardiogram is the main test to diagnose what valve is involved and how severe it is.

Treatment depends on the type and severity of the valve lesion. You may simply be monitored over years to see if anything changes. Some conditions require medication to thin the blood or treat any complicating heart problems. You may be referred to a heart surgeon for consideration of a valve replacement or dilatation of a narrowed valve.

A cardiac MRI is a special scan that uses large magnets and radio waves to create detailed pictures of the heart.

It shows both the structure and function of the heart, including the heart muscle, the chambers and valves and blood flow through the heart and major vessels.

It can be particularly useful in patients who have had prior heart attacks, heart muscle disease, valvular diseases and congenital abnormalities.

This test examines blood flow to the heart muscle using stress testing and a chemical known as a “tracer”, which is a short-lived radioactive agent. This scan is especially useful in determining whether heart artery disease is limiting blood flow, in assessing patients prior to major surgery, and in investigating patients with possible angina.

A limited number of cardiac nuclear tests are funded by Waitematā Health, and tests are carried out by New Zealand Medical Imaging.

CTCA is a CT scan of the arteries of the heart. By injecting contrast dye into a line in your arm, the scan can provide high definition, 3 dimensional images of your arteries. It is one of the best ways to detect signs of coronary atherosclerosis, (narrowing of the arteries), from plaques developing in the walls of the artery.  Coronary atherosclerosis may cause angina or a heart attack.

For this test you will require an IV line in your arm.  Your heart rate will need to be less that 60 beats per minute so good images can be obtained. You may require Beta Blocker medication to reduce your heart rate if necessary. GTN spray is given so the arteries are more easily seen.

Outpatient CTCA appointments can take up to 4 hours. The actual scanning time is only 5 minutes but the preparation and recovery period can take time. You can eat your usual meal prior to the appointment but should reduce your caffeine intake for the 24 hours prior to your appointment time.

After the scan you will remain in radiology for at least 30 minutes to make sure you haven’t had any reaction to the contrast dye. You will be encouraged to drink at least 6 cups of water over the rest of the day. Alcohol should be avoided on the day of the scan.