By Olivia Solon, Wired UK
A team of researchers have used datamining and machine learning techniques to find subtle changes in electrical activity in the heart that can be used to predict potentially fatal heart attacks.
They discovered several of these subtle markers of heart damage that could help doctors identify which heart attack patients are at a high risk of dying soon. Electrocardiograms (ECGs) are already used to monitor heart attack patients, but doctors tend to look at the data in snapshots rather than analyze the lengthy recordings.
The team developed ways to scan huge volumes of data to find slight abnormalities — computational biomarkers — that indicate defects in the heart muscle and nervous system. These included looking for subtle variability in the shape of apparently normal-looking heartbeats over time; specific sequences of changes in heart rate; and a comparison of a patient’s long-term ECG signal with those of other patients with similar histories.
They found that looking for these particular biomarkers in addition to using the traditional assessment tools helped to predict 50 percent more deaths. The best thing is that the data is already routinely collected, so implementing the system would not be costly.
Around a million Americans have heart attacks each year, with more than a quarter of those in groups who survive the initial attack dying within a year. Current techniques miss around 70 percent of the patients that are at high risk of complications, according to Zeeshan Syed, assistant professor at the University of Michigan Department of Electrical Engineering and Computer Science.
Syed explains: “There’s information buried in the noise, and it’s almost invisible because of the sheer volume of the data. But by using sophisticated computational techniques, we can separate what is truly noise from what is actually abnormal behavior that tells us how unstable the heart is.”
Doctors tend to look out for several factors in heart attack patients, including blood test results, echocardiograms, medical history and the patient’s overall health. Those identified as having a high risk of sudden death due to irregular heart rhythms can be given medication or implantable defibrillators, which can shock the heart back into its regular rhythm.
However, it’s hard to work out who needs these treatments before it’s too late — most people who die in this manner aren’t identified as candidates for implantable defibrillators.
MIT professor John Guttag explains: “We’re reaching a point in medicine where our ability to collect data has far outstripped our ability to analyze or digest it. You can’t ask a physician to look at 72-hours worth of ECG data, so people have focused on the things you can learn by looking at tiny pieces of it.”
The study was published in Science Translational Medicine.
Image: TheAlieness GiselaGiardino²³/Flickr