The acute and sudden pain in the chest represents the first cause of access to the emergency room (9 people out of 100) in the western world. This symptom can be the indicator of numerous pathologies, which are sometimes difficult to distinguish, especially in emergency situations. Among these are trivial clinical conditions, such as gastroesophageal reflux, and more severe ones, such as heart attack, pulmonary embolism or myocarditis. The patient who comes to the emergency room for chest pain usually has variable symptoms, complex related health conditions, and is often on multiple medications. Evaluating them is difficult. Usually the diagnostic process begins with a history, followed by an electrocardiogram (which takes a cardiac trace of the electrical activity of the patient’s heart), a chest X-ray and a coronary angiography (or coronary angiography), which allows, thanks to the use of a contrast medium and X-rays, to analyze the blood flow inside the coronary arteries in real time).
In about 50% of patients, the electrocardiogram (or EKG) can show changes in heart rhythm associated with a heart attack. The remaining 50% do not show an altered rhythm and need further investigations, including specific blood tests such as the cardiac troponin test. The latter is considered one of the most important methods for detecting the presence of myocardial infarction (necrosis of a part of the heart muscle caused by blockage of one of the coronary arteries), ischemic damage (lack of blood supply to the heart), inflammatory heart diseases and to rule out other conditions that cause similar signs and symptoms. Now a group of Indian and US scientists have developed a wrist device that could revolutionize the treatment of heart attacks by speeding up diagnosis, without the need to draw blood (the current method). The results of the experiment, published in the European Heart Journal – Digital Health, have shown that this device can detect 90% of heart attacks within five minutes. This new technology makes a vital contribution to emergency medicine.
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The troponin test
Troponin is a set of proteins found in heart cells and play a key role in making heart muscle cells contract and relax. When cells are starved of oxygen due to a blockage in the coronary arteries (which supply blood to the heart), the cells begin to die and release troponin into the blood supply. Normally the blood levels are very low, close to zero. In case of damage or serious suffering to the heart, troponin is released into the blood and can be determined with a simple blood test. Therefore, the troponin dosage is performed when symptoms suggesting a heart attack appear and in people who come to the emergency room with chest pains that suggest heart damage such as: chest pain at the level of the sternum with a sense of oppression and constriction, left arm pain, rapid heartbeat, cold sweats, difficulty breathing, fatigue, nausea, dizziness, pain radiating to other parts of the body such as back, arms, neck and stomach.
When troponin levels rise
We have seen that, in the case of myocardial infarction, the troponin values in the blood begin to increase after a few hours, reach their maximum values at the eighteenth hour after the onset of pain, and remain elevated for about 14 days. This is why the examination is performed 2–3 times within 12 to 16 hours of the onset of the complaints. A change in the amount of troponin in the blood can indicate a heart attack. This is especially useful for patients who show no change on the ECG.
If a heart attack is diagnosed, the patient is immediately subjected to angioplasty, a surgical procedure which involves the insertion of a balloon catheter in the coronary artery which is positioned in correspondence with the obstruction. Once inflated, the balloon pushes plaque against the artery wall, reopening the blockage and improving circulation. Usually, one or more “stents,” small wire mesh tubes, are also inserted and wrapped around the catheter before it is inserted into the artery and inflated. As the balloon is inflated and compresses the plaque, the stent expands and attaches itself to the artery wall, where it will then be engulfed by the vessel wall.
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How the wrist device that measures troponin works
Although the troponin test is one of the most reliable methods for diagnosing a heart attack, it has limitations: the test involves a blood draw which can cause anxiety and stress in some needle-phobic patients (4-10% of cases) with the risk of make chest pain worse. Not only that, it takes about an hour to get the results of the test from the laboratory. To overcome these limitations, researchers have developed an innovative wrist device capable of measuring troponin without taking any blood sample. The device is worn on the wrist like a smartwatch, and uses infrared rays that pass through the layers of the skin (transdermally) to detect troponin in the blood.
The device detects 90% of heart attacks within 5 minutes
The trial conducted on 238 patients hospitalized with chest pain at five sites, showed that this device can detect 90% of heart attacks within five minutes. “With this level of accuracy,” said the study’s lead author, Prof. Partho P. Sengupta, Chief of the Division of Cardiology at the School of Medicine of the Rutgers University (New Jersey) – if you use this device and it tests positive, you are pretty confident that this patient can be hospitalized for diagnostic testing, treatment and rapid interventions.”
“If larger studies confirm these initial findings, this breakthrough device could prove useful for early detection of heart attacks in emergency settings, such as emergency rooms, doctors’ offices, or ambulances, and for emergency services that first respond to a patient with chest pain,” concluded the researcher.
The device could also be used for other types of diagnosis
With the new wrist device it will therefore be possible to speed up the diagnosis of infarction and restore the correct blood flow to the heart as soon as possible in patients. But it might not just be heart attack patients who benefit from this device. The technology, according to the developers, could also potentially be used for other tests to detect blood clots, ectopic pregnancy or sepsis. And it could be a lifeline for all those people with severe needle phobia.
Credits: The wrist device (European Heart Journal – Digital Health)
Credits: Typical and atypical location of chest pain (Italian Journal of Cardiology)