Researchers have developed a non-invasive, reusable "ECG vest" that can capture high-resolution images of the heart's electrical activity in just five minutes. Combining its data with cardiac MRI scans could better identify people at risk of future heart problems and pave the way for more personalized treatments for heart disease patients.
Most people are familiar with the traditional 12-lead electrocardiogram (ECG), which consists of a set of 12 electrodes distributed in the chest and limbs to record the electrical activity of the heart and is used to diagnose cardiac abnormalities, such as arrhythmias that may lead to sudden cardiac death. However, the information a 12-lead ECG can provide is limited.
Currently, the heart's electrical activity can be mapped through electrophysiology (EP) studies, which require the insertion of catheters into the heart chambers. The invasive procedure usually takes about two hours, requires a small incision in the thigh or neck, and requires the patient to be sedated. Alternatively, electrocardiogram imaging (ECGI) can also be done with a CT scan that requires radiation.
Now, researchers at University College London (UCL) have given the 12-lead ECG a long-awaited upgrade, developing a non-invasive, time-saving, reusable ECG imaging vest that provides high-resolution images of the heart's electrical activity. Combined with cardiac MRI scans, the device can identify the risk of future heart problems.
"We identified a problem in cardiology," said Gaby Captur, the study's corresponding author. "Cardiac imaging has come a long way in recent decades, but the electrical aspects of the heart have always eluded us. The standard technique for monitoring the heart's electrical activity, the 12-lead electrocardiogram (ECG), has changed little in 50 years."
Traditional ECG electrodes are made of silver/silver chloride that can conduct ECG signals, and a layer of electrolyte gel is required between the conductors and the patient's skin. Such electrodes are easily damaged, cannot be reused, and can irritate the skin. 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 contains 256 snap-on electrodes connected to detachable leads and is made of 100% cotton, which is breathable and durable and can withstand high-temperature laundering.
To test the electrocardiograph vest, the researchers recruited 77 participants, including 50 older adults and 27 healthy young volunteers. The vest recorded the heart's electrical activity for five minutes while the participant rested on his back. Subsequently, a non-invasive cardiac magnetic resonance (CMR) scan is performed to create detailed images of the heart's structures. Combining EKG and CMR data, researchers can generate a three-dimensional digital model of the heart and its electrical activity.
"Cardiac MRI is the gold standard in cardiac imaging, showing us the health of the heart muscle tissue, including where dead muscle cells may be located," said Matthew Weber, first author of the study. "In-depth ECG imaging can help us connect these features to their consequences - the impact they may have on the heart's electrical system. It adds a missing piece to the puzzle."
The researchers say their electrocardiogram imaging vest could be an effective screening method for identifying the risk of future heart problems.
"We believe the vest we developed could be a rapid, cost-effective screening tool, and the rich ECG information it provides could help us better identify people at risk for developing life-threatening heart rhythms in the future," Kaptur said. "In addition, it could be used to assess the impact of medications, new cardiac devices, and lifestyle interventions on heart health. Currently, predicting [the] risk of sudden cardiac death is difficult because we don't yet know how, for example, specific structural features or abnormalities of the heart affect risk."
Researchers say better identification of the risk of arrhythmia could help health care providers determine which patients need devices such as implantable defibrillators.
Since the study concluded, the device has been successfully used in 800 patients. It is currently being used to map the hearts of patients with conditions such as cardiomyopathy. Longitudinal studies will confirm whether potential biomarkers obtained from electrocardiographic imaging can be used to predict risk.
The study was published in the Journal of Cardiovascular Magnetic Resonance.