Posted by Jenni Samuels. Note – New technologies are frequently highlighted by members of the Health Technology Forum either as part of this blog, at regular meet-up sessions or at the Annual HTF Conference being held on May 20th in San Francisco. For more information about HTF and the upcoming conference, please click here.
Innovative health technologies has the potential to benefit a range of clinical areas, but nowhere is this more important than in heart disease, which remains the nation’s biggest killer1, and for which health inequalities are still very apparent2. Around 720,000 people suffer a heart attack in the US each year and about 200,000 of these are repeat heart attacks3.
Although factors such as making changes to diet, exercise habits and exercise are important preventive measures4, close to half of heart attacks occur without any warning signs, with the rest of people experiencing symptoms suggestive of angina or another condition that may trigger a heart attack. For instance, an irregular heart beat may prompt a heart attack in someone with exiting heart disease5 and while pacemakers and internal defibrillators can be fitted, these devices are not ideal, as they are not custom-made.
However, new research led by Professor John Rogers, an expert in engineering and materials science from the University of Illinois, has developed a device that could revolutionize the treatment of heart disease and potentially prevent heart attacks. Their creation is an elastic silicone membrane, embedded with 68 sensors to gather information on the cardiac environment, which stretches over the surface of the heart to fit, making it more akin to a tailor-made device6.
Research into the heart sock
The first stage of the research involved fitting the silicone membrane over a 3D model of a rabbit’s heart to mould it into shape, which was then transferred to an actual rabbit’s heart in the lab7. This stage was crucial to find the right pressure, as if the device exerted too much pressure on the heart, it would interfere with the heartbeat. Although this “heart sock” still uses rigid materials, by avoiding right angles and completely flat sections in its construction, it is suitable for the flexibility required for cardiac tissue, with S-shaped wires able to stretch and bend without breaking8.
Information detected from the sensors was compared to the data gathered by imaging methods indicating that the sensors can correctly detect physical characteristics such as temperature, acidity and electrical activity in different parts of the heart. This could be used to spot unusual electrical activity that could signal a heart attack. As the sheath completely encloses the heart and could incorporate electrodes, the device could be used instead of a pacemaker to regulate someone’s heartbeat and might be able to intervene to prevent a heart attack.
Their research is now looking at how the sheath and the electrodes in it could be made to dissolve when someone no longer requires the device, offering a non-invasive and environmentally friendly means of disposal. So far incorporating a silk coating over magnesium and silicon shows great promise, as all elements are non-toxic and the silk lifespan is adjustable by altering its crystalline structure, potentially allowing the device to be kept for weeks or years as needed9.
Real life application
Trials of this heart sock in animals are set to start later this year. Although the team have only tested the device on one human heart from an organ donor so far, tests in living patients may not be so far away. Indeed, the medical staff these researchers are in collaboration with are keen to push forward with patient trials as soon as possible, owing to the fact that there are as over 250,000 deaths in the United States each year related to arrhythmias. However, the main challenge at the moment is developing a way to power the heart sock independently, possibly using a micro-scale battery, and communicate with the device wirelessly.
The other advance needed to get greatest benefit for therapeutic use is to add electrodes that can stimulate the cardiac muscle, so that the device can not only record potential problems with the heart, but act on these findings as well. Besides implanting the device within patients on a permanent basis, it will also prove useful during surgery, providing detailed cardiac data while procedures are underway. In addition, it will offer a useful research tool, allowing scientists to measure the electrical activity and changes in physical properties across the heart’s whole surface in real-time.
Use with other organs
While there is still a way to go before this heart sock is rolled out for use with patients, the researchers involved in this project are already considering how they might be able to adapt the device for use with other organs, as its ability to surround an organ’s surface makes it highly valuable. There is interest in using a similar device to monitor brain activity, though the limited space surrounding the brain would make it more challenging to attach. An area in which it may be easier to implement would be around the kidneys, as in renal disease such a device would give essential information about sodium, potassium and calcium concentrations10.