Researchers at the Massachusetts Institute of Technology (MIT) have developed an innovative, non-invasive pacemaker that stimulates the heart using ultrasound. The technology, which is currently still at an experimental stage, could eventually provide an alternative to traditional pacemakers that are implanted surgically.
According to the researchers, this development opens the door to a new generation of wearable medical technology that can not only monitor the heart but also actively treat it without the need for surgery.
A pacemaker patch
Traditional pacemakers are among the most commonly used implants in cardiology. Worldwide, millions of patients rely on these battery-powered devices to correct heart rhythm disorders. Although the technology is safe and effective, implantation always carries risks, such as infections, complications during the procedure or wear and tear on the electrodes.
The MIT team therefore developed an alternative in the form of a small, stamp-sized patch worn on the chest. The patch incorporates tiny ultrasonic transducers that send sound waves through the chest wall towards the heart.
These ultrasound waves activate specific ion channels in heart cells. When these channels open, calcium flows into the cell, causing the heart muscle to contract and thereby generating a heartbeat. According to the researchers, this approach offers the possibility of influencing the heart rhythm without direct contact with the heart or invasive implantation. The researchers presented their results in the scientific journal Nature Biomedical Engineering.
Sonogenetics
A key innovation behind the technology is the use of sonogenetics. This relatively new technique builds on the principle of optogenetics, in which cells are genetically modified to respond to light. In sonogenetics, cells are instead made more sensitive to sound waves.
The researchers genetically modified human heart cells so that the ion channels respond more strongly to ultrasound. In laboratory experiments, these modified heart cells were found to beat in sync with the applied ultrasonic pulses. Unmodified cells showed hardly any of this effect.
According to the researchers, a future treatment could begin with a single-dose gene therapy, similar to a vaccination. This treatment would make heart cells more sensitive to the ultrasonic signals from the wearable pacemaker. Although such applications still require extensive clinical investigation, they are in line with rapid developments in the field of gene therapy for hereditary and chronic conditions.
Successful tests in animals
In addition to laboratory research, the technology was also tested in rats with various cardiac arrhythmias. The researchers first administered a sonogenetic treatment, after which a miniature version of the ultrasonic pacemaker was placed on the chest.
The results were promising. In animals with a heart rate that was too low, the heart rhythm was increased to normal levels. Irregular heartbeats could also be stabilised, with the heart continuing to beat in sync with the ultrasonic pulses.
According to the researchers, this occurred quickly, safely and without visible damage to the surrounding tissue. The study thus demonstrates that ultrasound, in combination with sonogenetics, can be an effective way of regulating heart rhythm.
Wearable ultrasonic sensors
The ultrasonic pacemaker builds on earlier research by the same MIT group into wearable ultrasonic sensors. They had previously developed a patch capable of continuously imaging deep-seated organs and tissues using ultrasound.
The next step is to combine both technologies into a single system. A wearable patch could then not only monitor the heart but also intervene immediately when abnormalities are detected. Such a so-called closed-loop system could automatically combine diagnosis and treatment.
According to the researchers, the potential of this technology extends beyond cardiology. In the future, similar ultrasound patches could be used for long-term monitoring, imaging and targeted stimulation of other organs and tissues. Although clinical application is still years away, the research shows how wearable technology, ultrasound and gene therapy together create new possibilities for less invasive and more personalised care.
Less invasive pacemaker technique
Last year, cardiologist-electrophysiologists at the Haga Hospital demonstrated an innovative technique for pacemaker implantation. They showed how a pacemaker is inserted via the jugular vein rather than the traditional femoral vein.
The method was first used in Europe at the Haga Hospital six years ago and, according to the specialists, offers several advantages. Patients experience less pain, have a lower risk of post-operative bleeding and can usually go home sooner. In addition, the jugular vein provides a shorter route to the heart, making the procedure simpler.
