Typically, pacemakers correct an irregular heartbeat by delivering an electrical shock to the whole heart – which can be painful. An experimental new one takes a different approach and does so by surrounding the heart with light-emitting “petals.”

In a conventional pacemaker, one or two electrical leads are surgically anchored to the heart muscle. Whenever sensors in these wires detect an irregularity in the heart’s rhythm, they respond by delivering a corrective electrical shock. Unfortunately, this shock stimulates not only the muscle but also the cardiac pain receptors.

Based on previous research, a University of Arizona/Northwestern University team led by U Arizona Asst. Prof. Philip Gutruff set out to develop a less painful alternative. The resulting prototype consists of four flexible, petal-like, thin-layered structures that wrap around the heart underneath “like a flower that closes at night.”

Using a technique known as optogenetics, tiny blue LEDs in the petals turn on when needed to stimulate modified cells called cardiomyocytes—they cause the heart muscle to contract. Importantly, only cardiomyocytes are affected, leaving pain receptors unstimulated.

As an added bonus, because the optogenetic pacemaker uses LEDs to stimulate the cells but electrodes to monitor the heartbeat, it can perform both functions at the same time – traditional pacemakers have to switch between one or the other. In addition, no parts of the new device are actually placed in the heart itself, so its implantation is significantly less invasive.

The pacemaker’s petals include both cardiomyocyte-stimulating LEDs and electrodes for monitoring heart rhythm

Philip Gutruff

Another problem with traditional pacemakers lies in the fact that they are powered by batteries that must be surgically replaced when they begin to wear out. This would not be a problem with an optogenetic pacemaker, as it is powered wirelessly via resonant coupling technology. Gutruff tells us that the patients would must remain in close proximity to an external resonating device that can be worn on the body or built into objects such as mattresses or chairs.

The pacemaker has already been successfully tested on mice, but has not yet been tested on humans. This is described in an article that was recently published in the journal Scientific progress.

source: University of Arizona