If someone is afflicted with heart disease, it's important that their cardiac activity be monitored as frequently and accurately as possible. An experimental new wearable device is designed to make that happen, by copying the body structure of the starfish.
When it comes to checking people's hearts, a technique known as Doppler ultrasound is one of the most commonly used methods. It must be performed during a visit to a clinic, however, and requires the patient to remain immobile. This means it doesn't provide a true picture of how the person's heart performs most of the time, during most activities.
One alternative involves having the patient wear a system that monitors and logs their heart activity over the course of several days, as they go about their regular life. In order to record different types of cardiac signals, these systems typically must incorporate multiple sensors, each one of which has just a single point of contact with the skin. As a result, such setups tend to be complex, cumbersome and uncomfortable.
That's where the starfish-inspired device comes in.
Developed by Sicheng Chen, Zheng Yan and colleagues at the University of Missouri, the five-armed, flexible-polymer-bodied gadget is adhered to the skin over and around the patient's heart. No other wearable components are required.
At the end of each arm is a "sensing pad" consisting of an accelerometer and an electrode. Copper circuits run from each of those pads, down the length of the arm, to an electronics hub in the middle. Among other things, that hub contains a 32-bit microcomputer, a Bluetooth module, plus a rechargeable battery and wireless charging coils.
Between the five of them, the sensing pads record electrocardiogram (ECG), seismocardiogram (SCG) and gyrocardiogram (GCG) cardiac signals – ECG is the electrical activity of the heart, whereas SCG and GCG are mechanical. The pads also record mechanical signals generated by non-heart-related body movements.
All of that data is initially processed by the onboard computer, then wirelessly transmitted to a nearby smartphone or tablet for further analysis via machine-learning-based algorithms – this happens 10 times per second. For the purposes of the study, the algorithms were trained on cardiac readings from 16 healthy volunteers, and from 18 people with various heart conditions.
When tested, the technology proved to be over 91% accurate at identifying heart maladies such as atrial fibrillation, myocardial infarction (heart attack), and heart failure. Part of the reason for its accuracy – which should improve as the device is developed further – lies in its ability to differentiate between heart movements and other movements.
In its current prototype form, the gadget weighs just 1.7 grams and can run for up to eight hours before needing to be wirelessly recharged (while still on the wearer's body). It's presently adhered to the chest skin via a conductive gel, but future versions should utilize a more breathable, comfortable material.
"Most current devices focus on capturing only one signal or require separate devices to track multiple signals at the same time," says Chen. "This [one] allows us to provide a more complete picture of someone’s heart health."
A paper on the research was recently published in the journal Science Advances.
Source: University of Missouri
