If you develop chest pains, there are a wealth of tests you could be sent for to identify whether you have a heart problem.
And now NICE (National Institute for Health and Care Excellence) is supporting a new high-tech weapon in the diagnostic armoury, in the form of clever new medical software, HeartFlow.
It uses data from standard cardiac CT scans to produce virtual 3D models of the patient’s blood vessels, identifying any areas of narrowing that may require treatment, without the need for invasive tests.
It’s estimated the device could benefit tens of thousands of patients each year.
“If you could look at the heart in a way that didn’t require an invasive procedure like an angiogram, you could save people from the potential side-effects of invasive tests,” says Dr Mike Knapton, associate medical director at the British Heart Foundation (BHF).
However, although NICE provisionally supports using HeartFlow in certain patients, its final guidance isn’t expected until January 2017.
In the meantime, here’s a quick look at the current main diagnostic tests for heart problems.
Physical assessment
A doctor takes a patient’s medical and family history, asks questions about their lifestyle (such as how active they are and whether they smoke, etc), listens to their heart and lungs, and takes their blood pressure and pulse.
“If there’s a significant degree of clinical suspicion that a problem could be cardiac, the NHS encourages GPs to do a fast-track referral to a cardiology clinic within two weeks,” explains Knapton, who says a GP may also do blood tests and an ECG.
Blood tests
Blood tests are used in relation to a number of heart conditions, the most common types being cardiac enzyme tests, which help show if the heart muscle is damaged; full blood count, which measures different types of blood cells and can show, for example, if there’s an infection, and thyroid function tests, which detect an under or overactive thyroid, which can be linked to heart palpitations or a very slow or fast heart rate.
There are also BNP tests, which show hormone levels that may signify heart failure, and a U and Es (urea and electrolytes) test, which shows if there’s too much or too little sodium or potassium in the blood. These are important for overall heart function.
Chest X-ray
If you have symptoms such as shortness of breath, a chest X-ray can help ascertain if it’s caused by a heart or lung condition. If a heart condition’s suspected, further tests will be recommended.
Heart conditions that can be assessed by X-ray include heart failure, congenital heart disease and pericarditis (inflammation of the heart and lungs).
Angiogram
An angiogram lets doctors look inside coronary arteries, to see where, and how severely, they’ve narrowed, and how effectively the heart’s pumping.
Patients are given a local anaesthetic in the arm or groin, where a catheter is passed into the artery. Using an X-ray, the catheter’s directed through the blood vessels and into the heart before a dye is injected, which shows any narrowed areas or blockages.
There’s also a CT coronary angiogram, where the dye is injected into a small vein in the arm and a CT scan used to create an image of the patient’s heart.
Knapton says the standard coronary angiogram is the “gold standard” for diagnosing coronary heart disease – it also enables treatment, such as stents to widen arteries, to be performed simultaneously if necessary.
There would need to be significant risk of a heart problem for a coronary angiogram to be carried out, says Knapton. “It’s an invasive test and while it’s safe, there are risks like bleeding from the groin, so you’d want to be pretty sure the information you got from the angiogram was worth the risk to the patient,” he explains.
ECG
An electrocardiogram (ECG) records the rhythm and electrical activity of the heart, via electrodes attached to the arms, legs and chest with small sticky patches connected to an ECG recording machine. The test can help detect problems with the heart rate and show if a patient is having a heart attack, or has already had one. An ECG can also show if the heart is enlarged.
“There are certain patterns you can see on an ECG which could indicate coronary heart disease, along with lots of other potential abnormalities,” says Knapton. “However, a normal ECG doesn’t rule out significant coronary heart disease and other tests may be needed, such as a coronary angiogram or an exercise ECG.” (Where patients are wired up to the ECG machine while on a treadmill or exercise bike to see how the heart works during activity.)
Echocardiogram
An echocardiogram – also known as an echo – uses sound waves to create a detailed picture of the heart, similar to ultrasound scans.
A probe is moved over the skin of the chest, giving off pulses of high frequency sound waves which pass through the skin and ‘echo’ against the heart structures, reflecting them as moving pictures.
The echo also gives information about the heart’s function and pumping action. It can be useful after recent heart attacks or heart failure, and is also used to assess people with heart valve problems or congenital heart disease.
MRI scan
A cardiac MRI is used to view the heart’s structure and assess how well it’s pumping, so it’s useful for checking structural problems including congenital heart disease, wear and tear of the valves, heart damage after a heart attack, and the amount of healthy heart muscle if you have heart failure.
MRI scans can also look at the heart’s blood supply and related conditions, such as angina and coronary heart disease.
Sometimes a dye is injected into a vein in the arm, so images of blood flow to the heart show up more clearly on the scan.
Judgement call
“The reason we don’t do all the other tests willy-nilly, like we do blood tests, is that they’re significantly more bother – patients have to go to hospital, and with coronary angiography it’s invasive and there are risks,” explains Knapton.
“No test is 100% diagnostic – there will always be the need for medical professionals to apply clinical judgement, to assess what to do and how to interpret test results in the context of the individual patient,” he adds.
“It’s not just the tests that matter. It’s the judgement of the clinicians and the tests together that make the difference.”
