Researchers have developed a non-invasive, reusable 'ECG vest' that takes high-resolution images of the heart's electrical activity in five minutes. Combining its data with cardiac MRI scans can better identify people at risk of future heart problems and could pave the way for more personalized treatment of patients with heart disease.
Most would be familiar with the conventional 12-lead electrocardiogram (ECG), a set of 12 electrodes positioned around the chest and on the limbs that record the heart’s electrical activity and are used to diagnose cardiac abnormalities such as arrhythmias that can lead to sudden cardiac death. However, the 12-lead ECG is limited in what information it can provide.
Currently, mapping the heart’s electrical activity can be done by way of an electrophysiology (EP) study, which involves inserting a catheter into the heart’s chambers. The invasive procedure usually takes about two hours, requires a small incision to be made in the thigh or neck, and requires a patient to be sedated. Alternatively, electrocardiographic imaging (ECGI) can be done using CT scans requiring radiation.
Now, researchers from University College London (UCL) have given the 12-lead ECG a long-overdue upgrade, developing an ECGI vest that is non-invasive, time-efficient, reusable, and provides high-resolution images of the heart’s electrical activity. Combined with cardiac MRI scans, the device can identify the risk of future heart issues.
“We identified a problem in cardiology,” said Gaby Captur, corresponding author of the study. “Heart imaging has made remarkable progress in recent decades, but the electrics of the heart have eluded us. The standard technology to monitor the heart’s electrical activity, the 12-lead electrocardiogram (ECG), has barely changed in 50 years.”
Conventional ECG electrodes are made of silver/silver chloride that conducts ECG signals, with a layer of electrolyte gel separating the conductor from the patient’s skin. They’re easily damaged, can’t be reused and can cause skin irritation. So, the researchers used textile-based dry electrodes – made from conductive silver-coated polyamide yarn – that are comfortable, stretchable, gel-free, and can be washed and reused multiple times. The vest, which contains 256 snap-on electrodes connected to removable leads, is made from 100% cotton, is breathable and durable, and can withstand washing at high temperatures.
To test their ECGI vest, the researchers recruited 77 participants consisting of 50 older persons and 27 healthy young volunteers. The vest took five minutes to record the heart’s electrical activity while the participant was resting in a supine position. Afterwards, a non-invasive cardiac magnetic resonance (CMR) scan was performed to create detailed images of the heart’s structures. Combining the ECGI and CMR data, the researchers could generate 3D digital models of the heart and its electrical activity.
“Cardiac MRI, the gold standard in heart imaging, shows us the health of the heart muscle tissue, including where dead muscle cells might be,” said Matthew Webber, the study’s lead author. “In-depth electrocardiographic imaging can help us correlate these features with their consequences – the impact they may be having on the heart’s electrical system. It adds a missing part of the puzzle.”
The researchers say their ECGI vest could be an effective screening method to identify the risk of future cardiac problems.
“We believe the vest we have developed could be a quick and cost-effective screening tool and that the rich electrical information it provides could help us better identify people’s risk of life-threatening heart rhythms in the future,” Captur said. “In addition, it can be used to assess the impact of drugs, new cardiac devices, and lifestyle interventions on heart health. Currently, predicting [the] risk of sudden cardiac death is difficult, as it is not known, for instance, how risk might be affected by a particular structural feature or abnormality of the heart.”
Being able to better determine arrhythmia risk would help healthcare providers identify which patients need devices such as implantable defibrillators, which monitor the heart and shock the heart back into a normal rhythm if needed, the researchers say.
Since the study concluded, the device has been used successfully in 800 patients. It’s currently being used to map the hearts of people with diseases such as cardiomyopathy. Longitudinal studies will confirm whether there are potential biomarkers obtained from ECGI that could be used to predict risk.
The study was published in the Journal of Cardiovascular Magnetic Resonance.
Source: UCL
