Cardiovascular diseases, such as heart attacks and strokes, are a leading cause of death worldwide. However, many heart issues can be managed or even prevented with early detection and ongoing monitoring.
To that end, researchers from the Royal Melbourne Institute of Technology (RMIT) University have created a compact, wearable electrocardiogram (ECG) sensor that allows continuous, remote monitoring of heart activity. Weighing just 10 grams, this innovative waterproof patch could help prevent heart attacks in people with cardiovascular diseases.
Why continuous ECG monitoring matters
ECG plays a vital role in the early detection and ongoing treatment of cardiovascular diseases, such as stroke and coronary artery disease. People with heart ailments require regular ECG monitoring.
“Heart attacks often occur with little or no warnings, as signals are difficult to spot without continuous monitoring. Nearly half of the people having heart attacks do not realise what is happening until it is too late,” says Peter Francis Mathew Elango, the lead author of the study. Thus, continuous ECG monitoring is helpful in preventing such emergencies.
Reimagining the ECG sensor
Existing wearable ECG devices often have drawbacks that limit their effectiveness and comfort. They can be bulky and heavy and require ‘wet’ electrodes with conductive gel that can irritate the skin. The RMIT team set out to overcome these challenges.
“The focus of the team was on improving the electrode design and materials to increase performance as well as comfort,” said Professor Madhu Bhaskaran, deputy director (Research) of the ARC Hub for Connected Sensors for Health at RMIT, in a statement.
“The new sensor has only three ‘dry’ electrodes, which are extremely thin and can be easily recycled. They do not need any gel for optimum functioning and can sense the slightest signals of the heart. It is so small that it can fit even in the palm,” she said.
Electrode design and sensor fabrication
The dry electrodes were made from gold, which gave them various advantages, including being chemically inert, highly conductive, and biocompatible. The electrodes fabricated were extremely thin (150 nm) making them lightweight.
The research team explored various sensor design geometries to realise a compact and lightweight wearable ECG patch that would aid point-of-care (PoC) diagnostics. In the study, the team found that a hexagonal design is ideal as it suits the curvy nature of the skin and the users’ active lifestyles. It senses ECG signals more accurately than other commercially available sensors. This configuration was integrated with wireless Bluetooth communication, offering remote sensing capabilities and portability.
Putting the sensor to the test
The researchers integrated their optimised sensor design into a prototype wireless ECG patch to assess real-world performance. A volunteer wore the device while sitting, standing, and lying down, as well as during periods of rest and physical or mental stress.
The wearable patch successfully recorded ECG signals in all test scenarios, demonstrating comparable performance to a commercial 12-electrode ECG system. Remarkably, the sensor captured precise readings even when placed on the back of the neck.
“Our device efficiently captures the heart’s activity, whether the user is at rest or experiencing stress,” said Dr Bhaskaran in a statement.
Elango notes that this versatility makes the device particularly suitable for elderly users, such as those with dementia who might remove a chest-worn monitor. The sensor’s waterproof, gel-free electrodes also enable continuous wear during swimming or showering.
Enabling continuous monitoring
The RMIT team’s innovative ECG sensor offers a promising glimpse into the future of personalised, preventive heart health monitoring. By enabling comfortable, round-the-clock ECG tracking, this technology could empower individuals and healthcare providers to detect cardiovascular issues earlier and intervene more effectively.
“The dry electrodes offer significant advantages for continuous monitoring of the heart. Dry electrodes are comfortable, remain durable over time and reduce the likelihood of skin irritation,” says Elango.
This wearable sensor represents a significant step towards making continuous, remote heart monitoring a practical reality for millions worldwide.
“The device is user-friendly and is also suited for infant and aged skin. We are looking at a timeline of at least 5 years before we enter the market following field trials,” says Elango.
