Why you may need a pacemaker

Pacemakers are used to treat problems with low heart rates caused by diseases of the heart’s electrical system. Around 50,000 people in the UK are fitted with a pacemaker every year.

Common reasons for needing a pacemaker include a heartbeat that is too slow (bradycardia). This commonly arises from conduction system disease (particularly disease of the atrioventricular node) and sinoatrial conduction disease, sometimes known as “sick sinus syndrome”.

Overall the procedure to implant a pacemaker is very safe, and serious problems early after surgery quite rare. However, in the longer term problems are more common. Left bundle pacemakers are thought to reduce some of the long term problems of living with a pacemaker.

You can read more about the reasons why pacemakers are implanted on our main pacemaker page.

Problems with conventional pacemakers

Pacemakers use wires (“pacing leads”) placed into the heart to trigger heart beats. Wires can be placed into any chamber of the heart, and sometimes into veins on the surface of the heart, to control which parts of the heart beat early. However, until recently, little attention was paid to how the impulse generated by the pacemaker travels through the heart.

It turns out that when a pacemaker lead is placed a long way from the heart’s own natural electrical wiring, the beat travels more slowly through the heart. For most people most of the time this is not a problem. But if every heart beat follows this abnormal route through the heart then, over time, there is a risk of the heart becoming weak, in a condition called “pacing induced cardioymyopathy” or “pacing induced heart failure”. Over time this can can cause fluid retention and breathlessness, just like any other form of heart failure.

According to a series of academic studies (for example here), up to 1 in 4 patients receiving a high proportion of their heart beats from a pacemaker may develop cardiomyopathy over the long term.

How the Left Bundle Pacemaker is different

Pacing induced cardiomyopathy and heart failure develop when the electrical activity triggered by a pacemaker travels through the heart via a very different route to the heart’s normal electrical conduction system. Over time this causes dyscoordination and weakness of the heart muscle.

Since the early 2010s, doctors have experimented with trying to get pacemakers to trigger the heart’s own electrical system, so that beats generated by an artificial pacemaker appear exactly the same as a “natural” heart beat. This method has been terms “conduction system pacing”, and the various different methods have been named after the parts of the heart’s electrical system that they target, for example, His bundle pacing and Bachmann’s bundle pacing. These methods have proven effective at producing beats that look normal, but they are technically difficult, and with His bundle pacing especially, the results turned out to be unreliable in the longer term.

In 2019, Huang et al described implanting a pacing lead directly into the Left Bundle Branch, which is part of the heart’s own electrical conduction system within the ventricles (lower chambers). Like other conduction system pacing techniques, this method triggers a beat that spreads through the heart via exactly the same route as a natural heart beat. Unlike other methods such as His bundle pacing, however, the technique is a lot easier to learn and a lot more “forgiving” (i.e. small changes in lead position don’t seem to make much difference to the overall success of the procedure).

In fact, so long as the pacing lead is in the roughly the same area as the left bundle branch, the technique seems to work well. This has given rise to the term “Left Bundle Branch Area Pacing” or “LBBAP” to describe the technique.

On the day of a LBBAP implant

From the patient’s perspective, having a LBBAP implant is almost identical to having a normal pacemaker. In experienced hands the procedure is just as quick as a conventional pacemaker surgery. It still involves placing a battery at the shoulder, and wires down to the heart through the veins. The operation is usually done under local anaesthetic, with some sedative drugs used to allow the patient to doze through the procedure in most cases.

Occasionally it may be tricky to locate the heart’s electrical system and a few different positions may be trialled, making the procedure taken slightly longer than usual. Most implant procedures are over within 90 minutes or so.

Clinical trials

Like any new medical or surgical treatment, many trials are being carried out to confirm whether LBBAP gives significant advantages over conventional pacemaker implantation.

Early results are encouraging with non-randomised data from the I-CLAS database suggesting that LBBAP is as effective as other more established pacing techniques for treating heart failure. Small clinical trials where patients were randomised to either LBBAP or conventional CRT for heart failure produced similar results.

The major question of whether LBBAP can successfully prevent the development of pacing induced cardiomyopathy will be answered by Imperial College’s PROTECT-HF trial. Dr Idris Harding is principal investigator for PROTECT-HF at East Kent Hospitals and regularly undertakes LBBAP implants in Kent and at Kings College Hospital in London, which is also a PROTECT-HF centre.

Request a call-back to discuss a left bundle pacemaker