In some movies and TV shows it is sometimes shown that temporary pacemaker pacemakers need to be installed after certain heart surgeries to help keep the heart maintaining function. However, those temporary pacemakers usually require a wire to connect to an external generator that stimulates the heart, and after symptoms have improved, they need to be removed as appropriate, and these processes may add additional risk.
▲Image from: WIRED
To this end, researchers at Northwestern University and George Washington University (GW) have developed a wireless implantable device that can provide temporary pacing in 2021. Only 250 micrometers thick and weighing less than half a gram, it is soft and flexible, encasing electrodes that are softly laminated to the surface of the heart to deliver electrical impulses.
▲ Photo from: Northwestern University
This lightweight device can be used for patients who need temporary pacing after cardiac surgery or who are waiting for a permanent pacemaker. The device collects energy wirelessly from an external remote antenna using a near-field communication protocol and does not require an external wire.
What's more, all components of this pacemaker dissolve harmlessly in the body after they are not needed for use and are naturally absorbed into the body's biological fluids within about five to seven weeks, eliminating the need to perform surgery for extraction.
▲Image from: Northwestern University
Now, a team of researchers at Northwestern University led by John A. Rogers, Igor R. Efimov and Rishi Arora have refined the device again, developing a smart new version integrated into a wearable sensor. The new absorbable wireless pacemaker joins four other skin-interfaced devices to form a 'body domain network'.
▲ Photo from: Northwestern University
A battery-free bioresorbable pacemaker for temporarily pacing the heart; a cardiac module located in the chest powers the implanted pacemaker and controls the stimulation parameters and senses the electrical activity and sound of the heart.
▲ Photo from: Northwestern University
A hemodynamic module located in the forehead for sensing pulse oximetry, vascular tone, etc.; a respiratory module located at the base of the throat for monitoring coughing and respiratory activity; and a multi-touch feedback module that communicates with the patient in various patterns of vibrations and pulses.
Photo from: Northwestern University
The sensors continuously monitor various physiological functions in the body such as body temperature, oxygen levels, breathing and the electrical activity of the heart. The system then uses algorithms to analyze these activities in order to autonomously detect abnormal heart rhythms and determine when and at what rate to pace the heart.
This information is also transmitted to a smartphone or tablet, and the doctor can then monitor the patient's physical condition remotely. The haptic device will vibrate in a specific pattern to alert the wearer when the sensors detect problems such as incorrect device placement or a faulty pacemaker.
▲Image from: Northwestern University
While the previous device was flexible, the new device is flexible and resilient, better adapting to the changing heartbeat and releasing an anti-inflammatory drug in the process to prevent foreign body reactions as the pacemaker slowly and harmlessly dissolves.
What's more, the new device is able to provide on-demand pacing based on the patient's condition, and a chest-mounted heart module records ECGs in real time to monitor heart activity. In this study, the researchers compared this wireless technology to the gold standard ECG and found it to be as accurate and precise as the clinical-grade system.
▲Image from: Northwestern University
This also means that this simple and self-contained pacing system can automatically detect disease and administer treatment. It allows patients who need temporary pacing to recover without being limited by the equipment in the hospital and can be monitored remotely by a doctor, reducing healthcare costs while freeing up resources for other patients.
▲ Photo from: Northwestern University
The researchers also mentioned that this pacing system is most beneficial for fragile patients such as infants. Tens of thousands of babies are born with heart disorders every year, and many of these cases are life-threatening and require immediate surgery, after which they almost always require temporary pacemaker implants.
In about five to seven days, the pacemaker will no longer be needed once the heart has regained the ability to stimulate itself. Although the probability of complications during pacemaker removal is currently low, the availability of these absorbable wireless pacemakers will save the infant from a second surgery.