Soluble pacemaker vanishes after use
The first pacemaker to dissolve inside the body once it is no longer needed could make heart surgery safer, researchers have said.
The ultra-thin “transient pacemaker” requires no batteries and has been designed for patients whose hearts require temporary support.
All its components should degrade and be absorbed into the body over the course of five to seven weeks, ruling out the need for surgical extraction, its developers say. At present, to implant a temporary pacemaker electrodes can be sewn on to the heart muscle during surgery. These have leads that exit the front of the patient's chest, which are connected to an external box that delivers a current to control the heart's rhythm. The wires can be a source of infection, there is the risk that they will be dislodged and removing them can damage heart tissue.
Weighing less than half a gram the new pacemaker does not need any external connection or a battery. Instead it wirelessly harvests energy from a nearby antenna using near-field communication protocols, the same technology that is used in smartphones for electronic payments. The flexible device is attached to the outside wall of the heart using two stitches. It includes two metallic electrodes, which deliver the electrical pulses that help to control the heartbeat. Made of tungsten-coated magnesium, they are each about 0.05mm thick and are designed to dissolve, producing non-toxic materials. There is also a tungsten-coated magnesium coil, which collects the signal from the external antenna. You sent Today at 11:31 PMMost of the rest of the pacemaker is made from a polymer known as poly(lactide-co-glycolide), known as PLGA, that is already used in medical devices, and which also dissolves, and from candelilla wax, a plant product. By varying the thickness of the polymer casing, the lifespan of the device can be altered. Dr Rishi Arora, of Northwestern University in Illinois, who helped to lead the study, said: "Sometimes patients only need pacemakers temporarily, perhaps after an open heart surgery, a heart attack or drug overdose. After the patient's heart is stabilised, we can remove the pacemaker.
The current standard of care involves inserting a wire [but] these have potential to become infected or dislodged. "Instead of using wires that can get infected and dislodged, we can implant this leadless biocompatible pacemaker. "The circuitry is implanted directly on the surface of the heart, and we can activate it remotely. Over a period of weeks, this new type of pacemaker 'dissolves' or degrades on its own, thereby avoiding the need for physical removal of the pacemaker electrodes. This is potentially a major victory for post-operative patients.” So far the device has been tested on mice, rats, rabbits and dogs. in rats it completely degraded within three months of implantation.
It has also shown promising results when tested on human heart cells in the laboratory. Professor Sir Nilesh Samani, medical director of the British Heart Foundation, who was not involved in the research, said: “This is an exciting and innovative development which could be useful for some patients after cardiac surgery who develop a temporary problem with the electrical conduction of their heart beat. “This will need further testing to establish that it is safe and effective but, if this proves to be the case, then it could prevent patients ending up with permanent pacemakers unnecessarily.” The research was published in Nature Biotechnology.
Written and published by: Rhys Blakely | The Sunday Times
June 28, 2021
Originally published: https://www.thetimes.co.uk/article/vanishing-pacemaker-will-make-heart-surgery-safer-ctkx3htxs