A team of engineers has unveiled a promising new technology that could change the future of cardiac care. Researchers have developed an ultrasound pacemaker that regulates heart rhythms without surgery, wires, or implanted hardware.
The experimental system uses ultrasound waves delivered through a wearable chest sticker, offering a potential alternative to traditional pacemakers that require invasive procedures. Early testing showed the technology successfully restored healthy heart rhythms in engineered human heart cells and animal models.
How The Ultrasound Pacemaker Works
Unlike conventional pacemakers that are surgically placed inside the body, the new ultrasound pacemaker is worn externally as a small adhesive patch on the chest.
The sticker contains tiny ultrasound transducers that send carefully controlled sound waves through the chest and into the heart. Those waves activate specialized ion channels in heart cells, triggering calcium flow and prompting the cells to contract.
Researchers enhanced this response through a genetic engineering technique known as sonogenetics, which increases a cell’s sensitivity to sound-based stimulation.
Laboratory experiments demonstrated that ultrasound pulses kept engineered human cardiac cells beating in a healthy, synchronized pattern.
Researchers See A Future Beyond Implants
The project team has already built a working prototype that combines the wearable ultrasound patch with a compact device housing the necessary batteries and electronics.
The same research group previously developed ultrasound stickers capable of imaging organs deep within the body. Their next goal is to merge imaging and stimulation into a single platform capable of monitoring and regulating heart activity simultaneously.
“We believe you could one day have stickers on the body that could do long-term imaging deep in the body and also do stimulation for therapeutic effects, in a noninvasive closed-loop way,” says Xuanhe Zhao, professor of mechanical engineering and of civil and environmental engineering at MIT.
The findings were published in the journal Nature Biomedical Engineering through a collaboration involving researchers from MIT, the University of Southern California, Harvard University, and the University of California, Los Angeles.
Why Scientists Are Pursuing A Noninvasive Option
Pacemakers remain one of modern medicine’s most successful implantable devices. Roughly three million adults in the United States currently rely on them to regulate heart rhythms.
Still, implantation requires surgery and places hardware directly against heart tissue, creating risks that researchers have long hoped to avoid.
“Pacemakers are one of the most important and widely used human implants, and they have saved millions of lives,” the paper’s co-corresponding author, Gengxi Lu, says. “But they are invasive, and they make direct contact with the beating heart. The dream for many years has been noninvasive heart stimulation with ultrasound.”
Ultrasound technology already plays a major role in medical imaging. In recent years, scientists have also explored its therapeutic potential in treating neurological conditions including Parkinson’s disease and Alzheimer’s disease.
Previous animal studies suggested ultrasound could stimulate heart tissue as well, although the effects were often weak and inconsistent.
Sonogenetics Gives Heart Cells A Stronger Response
To overcome those limitations, the research team turned to sonogenetics.
The technique builds on principles similar to optogenetics, which uses genetic modifications to make cells responsive to light. Instead, sonogenetics engineers cells to react more effectively to sound waves.
Researchers modified heart cells derived from embryonic stem cells so they would respond more strongly when exposed to ultrasound.
“These channels can now ‘hear’ ultrasound better, and can open to let calcium in, which is what directly activates the cell and causes it to beat,” explains by the paper’s first author, Chen Gong.
When ultrasound was applied, the engineered cells contracted in sync with the sound waves, a result not seen in unmodified cells.
Gene Therapy Could Play A Key Role
Researchers believe future patients may receive a one-time gene therapy treatment before using the wearable device.
Such an injection would enhance the heart’s sensitivity to ultrasound, allowing the pacemaker patch to control heart rhythms from outside the body.
“We think this step would be clinically translatable as a form of gene therapy that could enable noninvasive pacemakers,” Gong says.
The approach would build upon existing FDA-approved gene therapies currently used to treat inherited conditions such as sickle cell disease and spinal muscular atrophy.
Successful Tests In Animal Models
The team also evaluated the technology in rats.
After administering a sonogenetic treatment, researchers attached miniature ultrasound stickers to the animals’ chests. Once activated, the patches rapidly corrected abnormal heart rhythms.
Animals experiencing slow heart rates returned to normal levels, while irregular heartbeats became synchronized with the ultrasound-generated pacing signals.
“We can now use low-intensity ultrasound to open ion channels in cells to have very effective heart pacing,” Gong says. “We are now making these stickers into smaller form factors, and more integrated, so they are easier to wear, more stable, and more accurate over a longer term.”
Potential Applications Beyond Heart Care
While cardiac pacing remains the primary focus, researchers believe the technology could eventually support a much wider range of medical applications.
The combination of long-term monitoring, imaging, and targeted stimulation could allow future wearable devices to manage conditions throughout the body without invasive procedures.
“In this paper, we demonstrated noninvasive pacemaking. However, we think this concept could be useful beyond just the heart,” Zhao says. “We believe you could one day have stickers over different parts of the body that could do long-term imaging, monitoring, and closed-loop therapeutic stimulation.”
The research received support from the National Institutes of Health, the National Science Foundation, the Department of Opthamology from Research to Prevent Blindness, and the U.S. Department of War.
