Over the years a number of different tests have been developed for the assessment of coronary artery disease. Coronary artery disease is the process whereby fatty deposits build up inside the walls of the arteries that supply the heart muscle. This fatty deposit is known by the medical term ‘atherosclerosis’. Over time this restricts the flow of blood into the heart muscle and causes angina. Angina is chest pain or discomfort, often described as tightness in the chest occurring on exertion and easing with rest. If these fatty deposits inside the artery suddenly burst this can lead to a heart attack.
There are a number of heart tests available to help diagnose whether there are any significant fatty deposits. The type of heart test required depends on a number of factors including the symptoms experienced and whether the test is an invasive or non-invasive investigation. A non-invasive test is usually less accurate than a test that involves placing needles and tubes inside the arteries. However non-invasive heart tests are usually much safer and involve less risk to the patient. The cardiologist usually determines the most suitable type of heart test by assessing the patient through their history and clinical examination. Sometimes a patient may be required to perform a particular heart test to allow them to continue their job. This is usually the case for patients who have suffered angina or a heart attack and who possess a DVLA Group 2 (HGV) driving license. Private hire taxi drivers may also be asked to have this type of test if they have suffered a heart attack to assess their suitability to drive.
Non-invasive heart tests
- CT coronary angiogram – a CT coronary angiogram is now the preferred test to investigate chest pain in suspected coronary artery disease. The scan can measure the ‘calcium score’ that is a measure of how much fatty deposit (also called atherosclerosis) is inside the heart arteries. The scan is the same as a CT scan and takes detailed pictures of the heart and heart arteries as well as other organs inside the chest such as the lungs. This heart test can indicate if the heart arteries are narrowed and the degree of the narrowing. The results can vary from normal arteries (ie no atherosclerosis or furring) to mild, moderate or severe narrowing. Once this information is known the cardiologist can create a detailed management plan for the patient.
- Exercise ECG – this is also known as a stress ECG, exercise stress test or treadmill test. This test involves walking on a treadmill that starts at a slow pace and gets progressively steeper and faster. If there are significant fatty deposits inside the heart arteries these will be detected in the form of ECG changes. Insurance companies can assess the suitability of a person for life insurance policies often use this test. It is also used by the DVLA to assess whether a person can continue to possess an HGV driving license. This type of heart test is available to patients of Dr. Hamaad who wish to have a healthy heart check.
- Stress echocardiogram – This heart test is similar to the exercise ECG but involves performing an ultrasound of the heart (an echocardiogram). An ultrasound scan of the heart is made before exercise (called the baseline scan). The patient is then made to walk on a treadmill at faster speeds and greater inclines until they reach their peak heart rate. The treadmill is then stopped and the patient’s heart is scanned again. The baseline and post-exercise scans are then compared to see if there are any changes in how well the heart beats which will provide clues about any areas of the heart that have arteries with a narrowing in them. For patients who are unable to walk on a treadmill, an injection of medication can be given that increases the heart rate and heart function to mimic what happens to the heart during exercise.
- Nuclear myocardial perfusion scan – This scan involves giving an injection of a radioactive dye through a vein. The patient is also given a drug that increases the heart rate and a scan performed to determine what areas of the heart have reduced uptake of the dye. This is a useful test to see if the blood flow is compromised through a narrow heart artery although it may not be suitable for everyone because it involves injecting a radioactive substance.
- Cardiac stress MRI scan – This particular heart test is similar to the stress echocardiogram. However an MRI scan is used instead of an echocardiogram. In addition, the patient receives an injection of a drug through their veins that increases their heart rate.
- Coronary angiogram – This is an invasive test that involves placing a catheter into the heart and injecting a dye whilst taking X-ray photographs of the heart. It is an invasive test and carries a small risk of complications such as a heart attack or a stroke. However, it is the most accurate way of determining the presence and severity of coronary artery disease.
The type of heart test that is most suitable will depend on the patient’s presenting symptoms and will be decided by the cardiologist. For most patients with chest pain suspected to be due to their heart, a CT coronary angiogram is considered the best test. For patients who are HGV drivers or taxi drivers the exercise stress test or stress echocardiogram may be required. All of these heart tests are available in Dr. Hamaad’s private cardiology clinic but will require a consultation prior to deciding the most suitable or appropriate test.
