In a statement, the hospital said the device is the size of a capsule and is implanted in a minimally invasive way, replacing traditional pacemakers (cardiac stimulators).

"Until now, only the Centro Hospitalar Lisboa Ocidental (Hospital Santa Cruz) and Centro Hospitalar Universitário São João (Porto) had performed this type of intervention," it adds.

The device is indicated for the treatment of patients with high-grade auriculo-ventricular block (BAV), a condition in which the electrical signals between the chambers of the heart (the atria and ventricles) are blocked.

This can result, among other things, in syncope or sudden death.

Currently, patients with AV block are treated with a pacemaker, implanted subcutaneously in the upper part of the chest, to which small electrical wires (electrodes) are attached and placed, through the veins, inside the heart, thus allowing the electrical connection between the atria and ventricles to be re-established.

"This new pacemaker, the smallest in the world, does not need electrodes, being placed directly inside the right ventricle, through a small access through the right femoral vein. There is, therefore, no traditional surgical scar, and the risks associated with the traditional technique, such as infections or electrode breakdown, are significantly reduced.

The first procedure at the Hospital de Guimarães occurred on 17 March and the patient has already been discharged.