There are several tests available to diagnose possible heart disease. How the physician decides which tests to perform (and how many) depends on factors such as your risk factors, history of heart problems, current symptoms and the physician’s interpretation of these factors.
The tests usually begin with the simplest and may progress to more complicated ones. Specific tests depend on your particular problem(s) and the physician’s assessment.
Tests that do not involve inserting needles, instruments or fluids into the body are termed non-invasive. Those that do, are called invasive tests.
Electrocardiogram (ECG)
This is the most common test for heart conditions. It is a simple, painless test that takes about 10 minutes.
Every time the heart beats, natural electrical currents can be picked up by electrodes placed on various points around the body. These natural electrical currents are recorded on paper. The tracing records the heart rate and rhythm and whether the muscle is conducting the electricity normally. Damaged heart muscle, or muscle that is short of oxygen, will result in a different appearance on the tracing.
The resultant tracing can give the doctor a lot of information about your heart, but, like most tests, the ECG is not infallible. If you have angina your heart tracing may be normal if it is recorded at rest when you are free of pain. In this case you may need an exercise ECG.
Holter monitoring
The purpose of Holter monitoring is to look for heart rhythm problems over a 24 to 48-hour period.
The Holter monitor is a small, portable, battery powered ECG machine worn when at home. It will record your heart rate and rhythm over a period of time. You will be asked to keep a diary of activities and any symptoms that you experience while the Holter monitor is being worn. At the end of the time period, the monitor needs to be returned to the hospital and a technician will view the recorded information.
Echocardiogram
This test uses sound waves to study the movement of the heart’s chambers and valves. This is particularly useful as you can assess different areas of the heart while it is beating. The echo sound waves create an image on the monitor as an ultrasound transducer probe is passed over the chest and heart.
Exercise stress test (treadmill test or exercise ECG)
Some heart problems only show up when the heart is working hard. To assess this, it is necessary to monitor the heart when you are exercising. A continuous ECG is done to achieve this. The test takes a maximum of 10 minutes.
You will be connected to an ECG machine and blood pressure monitoring facilities. You then walk on a treadmill which will slowly increase in speed and incline. At various stages you will have blood pressure and ECG recorded.
Echocardiogram stress test
This is similar to a resting echo test. It is performed on people who need to have a exercise ECG but are unable to walk any great distance due to mobility problems. Medication is given via an IV cannula to simulate exercise. Heart function and rhythm are monitored.
Cardiac catheterisation (angiogram)
Coronary angiography is an x-ray procedure used to examine the arteries of the heart. An introducing sheath is inserted into an artery, usually in your groin or sometimes an arm.
A catheter is threaded through this to the part of the aorta near the heart, where the coronary arteries start. A special dye is injected through the catheter, into your bloodstream.
X-rays of the heart and coronary arteries are then taken. The dye in your bloodstream helps highlight the coronary arteries and the narrowings in them. Your cardiologist will then review the X-rays and discuss the results with you.
Electrophysiological studies (EPS)
Your cardiologist might refer you for electrophysiology studies if you have an abnormal heart rhythm or palpitations. Fine tubes called electrode catheters are introduced through a vein and/or artery, usually in the groin. They are then gently moved into position in the heart, where they stimulate the heart and record electrical impulses. This type of investigation assists the doctor to make a definitive diagnosis and plan treatment for arrhythmia management.
Various blood test may be performed depending on your type of heart disease. These all help to build a picture of the nature of your disease.
Included might be assays for:
electrolytes
full blood count
hormone levels
blood clotting times
cardiac enzymes.
In recent years the most commonly used blood test to measure the level of cardiac muscle damage are proteins called troponins. The level of troponins in the blood helps to give a quick and accurate idea of the amount of muscle damage after a heart attack.
Cardiac troponin measurements help either confirm or exclude a heart attack in a person who may be having, or recently had, a cardiac event. They also help decide what treatments a person with unstable angina may need.
Troponin T and Troponin I are proteins that are part of the heart or cardiac muscle. When heart muscle injury occurs, these proteins are released. Troponin T and I are more sensitive to heart muscle damage than the enzyme creatine kinase (CK). This makes them a valuable test to detect mild heart attacks. They can be detected in blood as early as three hours after a heart attack associated chest pain starts. The levels peak at 10 to 24 hours and can still be detected up to five to 10 days later. This means that if you have had chest pain for several days a heart attack can still be detected.
raised blood cholesterol
obesity
nutrition
cigarette smoking
lack of physical activity
raised blood pressure (hypertension)
diabetes
stress
age
gender
previous history of heart disease
family history of heart disease.
Keeping blood cholesterol levels low
Lowering the levels of cholesterol in your bloodstream will lower your heart risk. The best things you can do to favourably affect your cholesterol levels are to:
eat and cook with less fat, especially saturated (animal) fat which is hidden in many snacks and foods
achieve and maintain a healthy body weight
be physically active.
Blood cholesterol is best measured as part of an overall assessment of your cardiovascular risk. This involves a simple blood test arranged by your doctor. Most people with heart problems should aim for a blood cholesterol level of less than 4 mmol/L (or even lower depending on your medical history and other heart risk factors). You can get more advice from your doctor, practice nurse or dietitian, or ask your doctor for our topic on High Blood Cholesterol.
If you are already overweight, you need to reduce your heart risks by losing weight and trimming your waistline. To do this you need to cut down, slowly and properly, on your food intake (particularly fats) and start to increase the amount of regular physical activity in your life. Avoid diets that promise rapid weight loss, and do not starve yourself or miss meals. You can ask for more advice from your doctor or a dietitian, or ask your doctor for our topic on Healthy Weight Control.
If you smoke, your chances of a heart attack are two or three times more than for a non-smoker, and you have a higher risk of stroke and many other diseases. Lifetime smokers have a 50% chance of dying from smoking-related diseases, and their lives are shorter by an average of 14 years. Smoking also affects the health of others around you. If you stop smoking, all the above risks soon become much less – quitting lowers the risk of a heart attack to that of a non-smoker within five years.
Active people have fewer heart attacks and have a better chance of recovery than inactive people. They also feel good and are less tired, more relaxed and better able to cope with stress. You can do more with less effort, have better heart function and possibly lower blood pressure. Regular activity helps control weight and lower blood cholesterol levels. Find different activities you enjoy and take opportunities to add physical activity to your day. You need not join a gym – regular brisk walking for half an hour can do the job.
Healthy physical activity should be:
regular – daily is ideal, three times a week is good, but anything is better than nothing
brisk – enough to increase your heart and breathing rates, not so hard it is painful or unenjoyable
sustained – the longer the better, but at least 15 to 30 minutes without stopping is good.
High blood pressure can enlarge and weaken the heart. It also damages the blood vessels which, if they become narrow or blocked, may result in a heart attack or stroke. Get your blood pressure checked regularly – and more often if you are older, taking any medication (including the contraceptive pill), overweight, or if you have diabetes or a family history of heart disease. To keep your blood pressure down you should maintain a healthy diet and body weight, exercise regularly, use less salt and, if you drink alcohol, do so in moderation.
People with diabetes are at greater risk of developing heart disease. Diabetes can affect vessels that supply blood to the heart. Working with your doctor to develop a plan to control your diabetes is the first step in safeguarding your heart. Many of the lifestyle changes suggested for keeping your heart healthy (ie, diet and physical activity) are important in controlling diabetes. Medication may be needed – ask your doctor.
Although it is now clear that factors such as family history and lifestyle are the primary problems, it is advisable for general health and wellbeing to know what stresses us unduly, and to find ways of dealing with it:
identify the cause
exercise regularly
relax physically and mentally
maintain healthy eating habits
establish regular sleep patterns.
Dr John J Ryan Medical Director.