This week I travelled to the Medtronic European headquarters in Lausanne for training in the implantation of the Micra leadless pacemaker.
Leadless pacemakers are an exciting development in cardiac pacing. Unlike a conventional pacemaker, there is no device under the skin and, importantly, there are no wires (leads) running from the pacemaker through the veins into the heart. The entire system is contained within the heart itself.
The Micra device is about the size of a large vitamin capsule and is implanted directly into the right ventricle through a vein in the leg. Once in position, it is secured to the heart muscle and can deliver electrical impulses whenever the heart needs them. Depending on the model and how much pacing a patient requires, the battery can last for many years – in some circumstances up to around 14 years.
Some newer leadless pacemakers can also detect atrial activity. This means that, in appropriate patients, they can provide a more sophisticated form of pacing than the original leadless devices.
Why avoid a pacemaker lead?
Conventional pacemakers have been used very successfully for many decades and remain an excellent treatment for many patients. They consist of a small generator implanted under the skin, usually below the collarbone, connected to the heart by one or more leads.
The leads are generally very reliable, but they are also the part of the system most exposed to certain long-term complications. These can include lead malfunction, infection and narrowing or blockage of the vein through which the leads pass.
This was brought home to me in my very first clinic after my leadless pacemaker training. I saw a patient who had undergone conventional pacemaker implantation about a year previously and had subsequently developed swelling and discolouration of the arm, particularly after playing netball. The symptoms were suggestive of narrowing of the vein containing the pacemaker leads.
This is not to say that conventional pacemakers are bad. For many patients, they remain the most appropriate option and have some important advantages over leadless systems.
Are leadless pacemakers better?
There isn’t a simple answer to this question.
Leadless pacemakers have now been used for almost a decade, and experience from large numbers of patients has demonstrated that implantation can be performed safely, with a relatively low rate of complications. The absence of a surgical pocket and leads eliminates some of the complications associated with conventional pacemakers.
However, leadless pacemakers are not suitable for everyone. They currently have limitations compared with conventional systems, particularly when patients need more complex pacing involving multiple chambers of the heart. There are also differences in how the devices are implanted, followed up and replaced.
For these reasons, I don’t think of leadless pacemakers as replacing conventional pacemakers. Rather, they give us another option, and in selected patients this can be a very attractive one.
Improving availability in the UK
One of the barriers to the widespread use of leadless pacemakers in the UK has been their cost compared with conventional pacemakers.
This year, NICE has recognised leadless pacemakers as a cost-effective option for appropriate patients. This should help increase their availability, improve insurance coverage, and, importantly, give clinicians and patients greater choice when deciding which type of pacemaker is most appropriate.
Which pacemaker is right for you?
The decision about which type of pacemaker to use depends on a number of factors, including the reason a pacemaker is needed, the patient’s heart rhythm, the expected amount of pacing required and their individual circumstances.
For some people, a conventional pacemaker will remain the best option. For others, a leadless pacemaker may offer significant advantages.
If you need a pacemaker, it is important to understand that there is more than one option. Seeing a cardiologist or electrophysiologist who is familiar with both conventional and leadless pacing can help ensure that the most appropriate approach is chosen for you.