More than 40,000 pacemakers are implanted every year in Spain. These devices are used so that the heartbeat does not stop in people who have alterations in the electrical installation of their heart.

They have become progressively smaller in size and there are even pacemakers today that do not need wires and are implanted directly into the heart. But they all carry risks and still need to be replaced when their battery expires.

This work presents an exceptional prototype. First, because it is a miniature, which can be transported using catheters, until it is implanted in the walls of the heart. Secondly, because the way in which the electrical impulses are generated is absolutely original. This opens up the possibility of being able to implant several devices that stimulate the heart simultaneously, increasing the efficiency of the contraction.

In short, this prototype is spectacular, but let no one forget that it is an experimental prototype. The idea is brilliant, but it will take years for this technology to be implemented in humans with sufficient guarantees. The prototype presented here only allows for transient stimulation, which could be useful for patients who require pacemakers only for a very short time. This is not the norm, because the norm is that people who need a pacemaker need it for life. However, that does not detract from the importance of these kinds of developments, which mark how fascinating medicine is going to be in the very near future.

In this work, published in Nature, the group of researchers has developed a new millimetric and resorbable stimulation device that allows for the effective stimulation of cardiac tissue from different chambers.

Among its main innovations is its size, which does not exceed 3.5 mm on its longest axis and is, overall, 23 times smaller than any other absorbable device developed to date. In addition, it offers a temporary stimulation capacity of up to 20 days, which makes it suitable for clinical applications that require temporary stimulation, such as in cases of infections in conventional devices that need to be removed or in the immediate postoperative period of cardiac surgeries, where the need for long-term permanent stimulation is not clear.

Another new aspect is the use of light in the infrared spectrum, which allows the phototransistor of the device itself to be stimulated practically from the surface of the chest.

Despite its advantages, this device has certain limitations. It is not applicable to all clinical scenarios, as its current design does not allow for permanent stimulation for months or years. In addition, it requires a light source in the near-infrared spectrum, which could pose a clinical problem both because of the possible discomfort of the light and because of the appropriate location of the source.

The implantation procedure, although minimally invasive, can be complex if it is performed on the surface of the heart. In this case, percutaneous implantation could involve more significant complications than those of conventional devices currently available. Likewise, stimulation from the surface of the heart is not physiological and could contribute to heart failure in prolonged stimulation.

For this reason, the viability of implanting this type of device in more physiological regions has not been addressed in this study and would require further research to determine its clinical applicability.