A newly developed blood test could quickly and accurately diagnose or rule out a heart attack, scientists including one of Indian origin say.

Researchers at King's College London investigated how many heart muscle cells needed to die before they could be detected in the blood stream.

In patients suspected of having suffered a heart attack, only a small proportion are shown as having diagnostic changes on a heart trace or electrocardiogram (ECG).

This means that their assessment is reliant on the use of blood tests measuring biomarkers such as cardiac Troponin (cTn) to exclude a heart attack.

Troponin is a heart muscle protein released upon injury and can be detected after heart attacks or heart muscle inflammation.

As a result, doctors are able to rule-out heart attacks with a single blood test, as patients with undetectable levels of cardiac Troponin are classified as low risk and are immediately discharged.

However, in the new study of over 4,000 patients at St Thomas' Hospital, scientists found that 47 per cent fell into the intermediate risk group, requiring an extended period of observation and further blood tests.

Using donated human heart muscle tissue, the team found that between 3-9 milligrammes (mg) per 0.001 per cent of the entire human heart had to undergo cell death to be detectable in the blood stream.

However, the new blood test showed that cardiac myosin-binding protein C was found to be even more sensitive, detecting 0.07 mg per 0.00002 per cent of damaged heart muscle.

"This new test could transform the way we diagnose heart attacks, improving the sensitivity and ensuring that heart attacks are not missed when troponin levels in the blood are extremely low," said Professor Nilesh Samani, Medical Director at the British Heart Foundation.

"This has the potential to transform the way we diagnose heart attacks in the 21st century," said Tom Kaier, Specialist Registrar in Cardiology at King's.

"We are looking at improving the experience of patients by developing new and more sensitive blood tests that could help doctors assess the amount of damage quickly and avoid patients being admitted overnight, unless truly necessary," said Kaier.

The research was published in the journal Clinical Chemistry