For more than 60 years the pacemaker (the small device implanted in the chest to send electrical impulses to the heart) has done its duty, producing a little beat in hearts that they could not make on their own.
The device has prolonged the lives of many patients (in its "extreme" version, ECMO, even pauses death). However, even the best pacemaker ignores one simple fact: healthy hearts do not beat as precisely as metronomes. They accelerate when we inhale, decelerate when we exhale. Based on this natural variation called “respiratory sinus arrhythmia” scientists around the world are creating a bionic pacemaker.
“The devices must listen to the body's feedback. We need smarter tools,” says Julian Paton, professor at the University of Bristol in England and leader of several research in this field.
In a paper published this week on the Journal of Physiology, Paton and his colleagues describe a bionic pacemaker that follows the heart's natural rhythms, compensating for fatigued ones more efficiently.
The device "reads" the electrical signals provided by each person's breathing, and regulates the heartbeat accordingly. In other words, it adapts perfectly to everyone's personal rhythm.
In tests on mice with heart failure, the device increases the blood the heart can pump by 20% compared to traditional pacemakers.
Far ahead of the present
Current pacemakers try to adapt to changes in a rather old-fashioned way, with the use of accelerometers or body temperature sensors. Some new devices are starting to appear on breathing, but they only adjust based on a periodic "sample" of recorded breathing. “We are modulating the cybernetic pacemaker around the different and unique breathing that each of us has,” Paton points out.
The heart of the cybernetic pacemaker? It is a mind
The device behind the bionic pacemaker uses an analog chip based on a neural network and developed by the co-author of the study, Alain Nogarett from the University of Bath. In tests on mice, she recorded electrical activity from the diaphragm muscles, which contract during breathing. The chip interpreted the signals and translated them into consequent electrical stimulation actions of the left atrium of the heart, to make it beat in "cooperation" with breathing.
The advantage of using an analog chip is that there is no mediation, and it can respond quickly to body changes: the device can be miniaturized to the size of a postage stamp.
Possible progress
If the tests on humans confirm the good premises of those on mice, Paton says, there will be no need to record the signals of the diaphragmatic muscle: just integrate the chip into existing pacemakers.
