When was the internal pacemaker invented?

The first internal pacemaker was developed in 1958 by Dr. Paul Zoll, who implanted electrodes in the heart to regulate its rhythm. However, the first fully implantable pacemaker was created by Dr. Arne Larsson in 1958 as well, and it was successfully used in a patient. These innovations marked significant advancements in cardiac care, allowing for better management of arrhythmias and heart conditions.