In one of our workshops with Alex Dickinson on prosthetics and orthoses, he bought in a cardiac pacemaker to show us. I was shocked as it was bigger than I thought it would be. It got me thinking that I had never done any research into pacemakers even though they are very common, especially in my life as my grandfather and uncle both have one. In this post I go into how pacemakers were developed into what they are now and also how they could evolve in the future to be better suited to their roles.

What is a Pacemaker?

A pacemaker is a small electrical device that is implanted into the chest of the patient with a number of leads attached that feed into the heart through a vein. They work by taking over the role of the sinus node. The sinus node is the hearts natural pacemaker that initiates the heartbeat by generating the signals that are conducted to the atria and ventricles to allow them to contract. A pacemaker has the ability to send electrical signals to the heart to cause it to pump and produce a heartbeat when the sinus node will not function properly. Pacemakers can be fitted for a number of conditions but mainly for heart arrythmias or heart blocks. A lot of pacemakers now a days work on demand, they use sensors that can tell when the heart is beating incorrectly or has missed a beat.

The development of pacemakers

In the 1930’s the development of the pacemaker began with Albert Hyman. He discovered that setting up a current using a needle to puncture the wall of the heart restarted it. He then invented the first ‘artificial pacemaker’. It was an external contraption that was spring-wound hand-cranked and rather large. The development of external pacemakers was continued throughout the 1950’s by Dr Aubrey Leatham and Geoffrey Davies. In 1958, in Sweden the first ever pacemaker was implanted into the chest of Arne Larsson by Rune Elmqvist and Ake Senning. However, this pacemaker only lasted for about 8 hours and Larsson had to have over 20 more replacements of his pacemaker. This would’ve been rather tough for him as the surgery to implant it was a lot more invasive at the time compared to now. Now a days implantation of a pacemaker is done under local anaesthetic and only takes about an hour. Another problem with these initial pacemakers was the size of them was rather bulky and their battery life was not very good.

Where next?

Pacemakers in today’s time have developed a lot since the times of Elmqvist and Senning. There are pacemakers that can have different numbers of leads e.g. one lead for a single chamber or a biventricular pacemaker has three leads. There has been developments recently into the creation of a fully leadless pacemaker that is a lot smaller than the current model and is implanted directly into the heart. This would be a less invasive option meaning that not only is the risk of infection decreased but also the recovery time would be too.