Pacemakers have been instrumental in extending and improving the lives of millions for decades. These small devices are implanted inside the body to send electrical signals to the heart whenever its natural rhythm slows down or becomes irregular.
Regarded as one of the most successful medical inventions, pacemakers have saved countless lives by helping maintain a steady heartbeat.
Although effective, traditional pacemakers still require surgical implantation. Surgeons must place the device in the chest and connect wires directly to the heart. While generally safe, this procedure carries certain risks, including infections, bleeding, and complications from hardware placement. For years, scientists have sought ways to regulate heart activity without invasive surgery.
Recently, researchers at MIT have made a significant breakthrough. They developed a compact, wearable device that uses ultrasound rather than electrical wires to stimulate the heart. This innovation could eventually lead to a fully noninvasive alternative to conventional pacemakers.
The device resembles a small sticker that attaches to the chest, with tiny ultrasound transducers embedded inside. These transducers emit precisely controlled ultrasound waves through the chest wall toward the heart.
Instead of electrical impulses, this system uses sound waves to influence heart cells. The ultrasound triggers the opening of specific channels on the cells, allowing calcium to flow in. Calcium entry is essential for heart contractions, signaling the cells to squeeze and generate a heartbeat.
To enhance effectiveness, the scientists employed a technique called sonogenetics, which involves making cells more responsive to ultrasound. They genetically modified heart cells so they would react more strongly to sound stimulation, making them easier to control with low-intensity ultrasound waves.
Initial tests were conducted in the lab with human heart cells derived from stem cells. When ultrasound was applied, the modified cells contracted in sync with the sound pulses. Their response was significantly more vigorous than that of unmodified cells.
Following promising lab results, experiments moved to animal studies. The team created a miniature ultrasound sticker device and placed it on rats’ chests. The results were promising: the device quickly corrected abnormal heart rhythms and restored normal heartbeats without invasive surgery or direct contact with the heart tissue.
The researchers envision a future where patients might undergo a single gene therapy session to increase heart cell sensitivity to ultrasound. Afterward, a wearable sticker could be used to manage heart rhythms as needed, potentially removing many issues linked with implanted devices.
This research builds on previous work by the same team, who previously developed wearable ultrasound devices capable of imaging deep tissues. Their ultimate goal is to combine both technologies into a single system.
One sticker could continuously monitor the heart and deliver treatment whenever irregular rhythms are detected, creating a closed-loop system. Such a device could identify problems early and respond automatically, potentially enhancing patient safety and reducing frequent hospital visits.
The applications could extend beyond heart care. Since ultrasound can safely penetrate various tissues, similar devices might eventually be used to diagnose and treat disorders across different organs and systems.
However, several hurdles remain before this technology can be used in humans. Current results are based mainly on lab and animal studies. Further research is necessary to confirm safety, effectiveness, and reliability in people. Regulatory approval and large-scale clinical trials will also be required.
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The full study has been published in *Nature Biomedical Engineering*.