Cardiac pacemakers emit regulated electrical impulses to stimulate the contraction of the heart muscles. This provides a sufficient rate of heartbeat. Cardiac pacemakers were developed in the 1960s. This pacemaker had to be carried at all times. It connected to electrodes attached to the heart. These generated an electronic impulse. People whose heart beat is too slow or who have a condition that impairs the electrical pulses are given pacemakers. Pacemakers are now implanted into the chests of patients rather than being carried externally like the E4162. This external cardiac pacemaker was made by the Implants Division of Devices Limited. It made a range of cardiac appliances.