- Researchers based in Australia and India recently published a study with their findings on developing improved electrodes for wearable heart monitors.
- The scientists researched options for developing a “dry” electrode, which they believed would provide benefits over the standard “wet” electrode.
- The researchers found that electrodes with gold films in a hexagonal labyrinth shape provided the most benefits.
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One way Healthcare providers try to detect heart conditions or prevent deaths related to heart disease is to use electrocardiogram (ECG) units to track heart activity. Doctors are able to catch changes in heart activity on ECGs that may show evidence of an irregular heartbeat or arrhythmia.
While some people wear ECG-capable smartwatches to monitor heart activity, doctors typically use in-office ECG machines or ask patients to use a standard wearable ECG device such as the Holter monitor.
With the standard wearable ECG monitor, the unit uses “wet” electrodes to measure heart activity. The electrode transmits signals through a gel.
The study authors believe there are drawbacks to wet electrodes and set out to create a “dry” electrode that does not rely on gel to transmit signals. Additionally, their device utilizes Bluetooth technology to send results to a smartphone app.
Their results appear in Applied Physics Reviews.
When healthcare providers suspect someone may have a heart condition or when someone complains of chest pain or heart palpitations, doctors may order an ECG to get a reading of the heart’s electrical activity.
In the clinical setting, providers place electrodes on the body and connect them to the ECG machine, with the test taking place over a few minutes.
Shorter ECGs performed in the office may not pick up on all heart issues, so providers may request their patients use a wearable ECG device.
Dr. Paul Drury, a board certified cardiologist and associate medical director of electrophysiology at MemorialCare Saddleback Medical Center in Laguna Hills, California, spoke with Medical News Today and explained the importance of wearable ECGs.
“Wearable ECGs are a very commonly prescribed and very clinically important tool used to detect and diagnose various cardiac arrhythmias,” said Dr. Drury. “Whereas a standard ECG records only 10 seconds of data, wearable ECGs can be worn for up to 30 days, which greatly increases the ability to detect these rhythms.”
When people use wearable ECG monitors, they have to put gel on the electrodes when putting them in place. The researchers say these electrodes can be problematic for users and can cause skin changes or otherwise be uncomfortable.
To this end, the scientists wanted to develop a dry electrode for wearable ECGs that does not require gel.
The study authors decided to use a thin film of gold in the three-electrode design because “it gives the added advantage of having an electrode that is chemically inert for all biological processes, highly conductive, and biocompatible.”
Additionally, the gold film allowed the scientists to create a lighter-weight electrode with a larger surface area, increasing its capability of picking up ECG signals.
After choosing the material type, they created electrodes of various shapes and tested them in different places on their test subject’s body to see how they performed.
The researchers designed six electrode designs to test. These shapes included:
- triangular labyrinth
- Peano curve
- circular labyrinth
- hexagonal labyrinth
- square labyrinth
- Hilbert curve
They tested the dry electrodes in the chest and neck areas of the participant’s body and while the participant was in various positions, including sitting and standing.
They also checked the signals under different stimuli, including at rest, under mental stimuli, physical stimuli, and a combination of mental and physical stimuli.
The authors say the hexagonal labyrinth, square labyrinth, and Hilbert curve designs were all “suitable” but that the hexagonal labyrinth was the best option for the prototype because of “its relatively better conformability and its ability to establish intimate contact on both the anterior of the chest and posterior of the neck region.”
They also say the results showed that the hexagonal labyrinth design had results comparable to commercial ECG units when they tested the results against the Welch-Allyn ECG model.
The researchers had the test subject wear the hexagonal labyrinth prototype for seven days to ensure it did not cause skin changes. They reported detecting no “skin irritation, rashes, or allergies.”
While more testing is needed, the authors suggest potential uses of the design across multiple settings including, “athletic performance, in neonatal care, rehabilitation, aged care sectors, patient transport, cardiac monitoring of patients with pacemakers, and patients with dementia.”
When Dr. Drury spoke with MNT, he touched on why patients might prefer using dry electrodes instead of wet electrodes.
“The development of dry electrodes would be very useful for a number of patients,” noted Dr. Drury. “Many patients develop skin reactions to either the adhesive or gel used with wet electrodes after prolonged use.”
Dr. Drury also said that once the gel dries out, they cannot collect information from the electrodes.
“A breathable and dry electrode would expand the patient population to those with skin sensitivities or allergies and those who would like to remain very physically active while wearing the ECG,” commented Dr. Drury.
While Dr. Drury thinks that dry electrodes could lead to more people being able to use wearable ECGs and lead to earlier detection of heart issues, he did note that the gold electrodes could be cost-prohibitive for some people.
“The dry ECGs also rely on gold in the electrodes which will likely lead to high cost of the product,” noted Dr. Drury.
Alex Starnes, advanced practice registered nurse, who works in trauma surgery at Piedmont Medical Center in Rock Hill, South Carolina, also spoke to MNT about the study.
“The size and lack of adhesive will make this much more comfortable for patients to wear and increase the likelihood of them keeping it on so they can be properly monitored,” Starnes commented.
“The 3-electrode design makes it more user-friendly and leaves less room for error in placement,” she noted.
While Starnes is impressed by the prototype’s capabilities, she does have questions the study authors did not mention.
“The study mentions transmitting information to a phone app, but does the information get stored anywhere else?” Starnes questioned. “Does the ordering healthcare provider have access to it in real-time or can they just go back and see what was uploaded to the app?”
She pointed out the significance of the provider having real-time access to the results.
“It is beneficial to review, say, two weeks of heart rhythms at a time to evaluate for intermittent arrhythmias, but it wouldn’t allow for real-time interventions if someone went into a lethal arrhythmia unless a qualified healthcare provider was constantly monitoring the rhythms,” she warned.