Fingerprick blood test that spots heart attack in minutes

HEART attacks may soon be diagnosed with a drop of blood, new research suggests.

Patients experiencing chest pain could be given the new fingerprick test by ambulance workers on the scene, allowing them to know within 15 minutes whether or not a heart attack had occurred.

It would mean patients could be diagnosed before they get to a hospital and ensure they are given the right treatment as soon as possible.

There are a million A&E visits in the UK each year linked to chest pain, but two- thirds of cases turn out not to be down to a heart attack.

The new test works by measuring levels of a protein in the blood that rises if the heart muscle is damaged. Studies have shown it to be highly accurate in spotting whether a heart attack has occurred, and it requires very little blood.

Scientists at King’s College London are now developing a portable device – similar to a blood glucose machine – so the test can be used in ambulances.

‘ We hope t hat within t he next year or two we will be able to give a prototype to paramedics,’ said lead researcher Dr Thomas Kaier.

Trials have used blood taken from patients’ arms and it’s likely that the first device will do the same. However, the test is so sensitive that the researchers say it will be possible to later create a fingerprick test.

A heart attack, also known as myocardial infarction, occurs when the blood supply to the heart is suddenly blocked, for example, by a blood clot.

Shortness of breath, lightheadedness and chest pain are among the symptoms.

People having a suspected heart attack will be given an ECG – or electrocardiogram – which measures e l e c t r i c a l activity in the heart.

They will also be tested in A&E for high levels of a protein called troponin, which is found in the organ’s muscle and released when it is damaged. But this test has to be repeated three hours later to get a more certain result. It also requires a large sample of blood and can take more than an hour to be processed in the laboratory.

The new test measures levels of a substance known as cardiac myosin- binding protein C or cMyC, which rise quickly in the blood after a heart attack.

In a new study, the researchers analysed blood samples from 776 individuals having a suspected heart attack in ambulances in Denmark. On average, they had experienced their symptoms for 70 minutes when the sample was taken.

Concentration of cMyC was much higher in patients who had suffered a heart attack.

The test was found to be effective at ruling out a heart attack in patients with other conditions after just a couple of hours of symptoms.

‘After two hours you can be certain t hat, i f you do our blood test and it’s negative, you did not have a heart attack,’ Dr Kaier said.

Current guidelines state the troponin test should not be used until the patient has had three hours of symptoms.

The cMyC test was also found to rule out three times as many heart attacks in a single blood test than the troponin test.

The researchers believe diagnosing heart attacks sooner will improve care for patients.

‘If you can be reassured earlier that you are unlikely to have had a heart attack then a lot of stress and concern is taken away from you,’ Dr Kaier said.

‘And if we know early that you are highly likely to have had a heart attack, that helps us know you might benefit from treatment – such as blood-thinning drugs – or you should be sent to the nearest specialist hospital.’

Prof Jeremy Pearson, of the British Heart Foundation, said: ‘ Big heart attacks are often easy to diagnose with an ECG but smaller ones, which are more common and also life-threatening, are more challenging.

‘ The troponin test has been used for 20 years and is the most powerful tool we have for diagnosing such heart attacks, but there i s a l ways room for i mprovement. These i nitial results with the cMyC test look very promising.’

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