New Ventricular Lead Placement Methods

Deep research!

by Lavender - 2022-08-19 22:07:52

You certainly will be well educated by the time you get your pacemaker! I am not nearly as well versed on the subject as others. I can say though that I was told in 2010 that I had intermittent left bundle branch block. I had no symptoms and it was discovered by accident when in the hospital for a pulled chest muscle. 
 

I was told that one day I would need a pacemaker. I always thought it would have been better if there was a way to correct the left bundle branch block. When I was in for the pacemaker implant in 2021, I was told that I had AV block. They said I had conduction disease and it was progressive. 
 

My pacemaker is a CRT-P. When it was chosen-it was up to the EP and cardiologist to chose which device and how it would be placed. I have a lead in each ventricle and one in the right atrium. The surgery to place it took three hours. 
 

I read this in your article mentioned:
 

In patients with bundle branch block (BBB), conduction system pacing can deliver cardiac resynchronisation therapy (CRT) by correcting BBB to synchronise ventricular activation.

 I understand that my CRT-P synchronizes the ventricles. I wonder if they could come up with a device that would fix LBBB long before it progressed to the AV block. I am encouraged reading all the research into new pacing. I have six years left on my device. I fully expect new developments will lead to an improvement in pacemakers by then. If I am still alive-God willing. 
 

This statement shows that more clinical trials need to be conducted to prove the new methods:

More stable and distal conduction system pacing in the left bundle branch region is a newcomer to the field of physiologic pacing and early evidence suggests it shows promise.

Randomised controlled clinical trials of the new forms of pacing for bradycardia and resynchronisation therapy are lacking and are essential to gain additional evidence related to the risks and benefit of this approach.

Lead placement positions

by Gemita - 2022-08-20 08:06:45

Hello FG, Thank you for the additional link and for your enthusiasm in moving this important subject forward.  Between us I think we have gathered some useful information to help us to understand the various lead pacing positions that are currently in use, the potential advantages and disadvantages of each one, the primary indications for the use of conduction system pacing.

As we may have read, traditional right ventricular apical pacing (RVAP) may cause electrical and mechanical dyssynchrony, which is associated with an increased risk for atrial arrhythmias and heart failure.  Although His bundle pacing (HBP) has been widely used as a physiological pacing modality, it is limited by challenging implantation technique, unsatisfactory success rate in patients with wide QRS wave, high pacing capture threshold, and early battery depletion. Recently, the left bundle branch pacing (LBBP), defined as the capture of left bundle branch (LBB) has emerged as a newly physiological pacing modality. Results from early clinical studies have demonstrated LBBP's feasibility and safety, with rare complications and high success rate. Overall, this approach has been found to provide physiological pacing that guarantees electrical synchrony of the left ventricle with low pacing threshold.  LBBP may be a potential alternative pacing modality for both RVAP and cardiac resynchronization therapy with HBP or biventricular pacing (BVP). 

I noted with interest in the link you provided FG that one of the indications for conduction system pacing was slowly conducted AF which is what my husband suffers from.  Slowly conducted AF isn’t really of concern to his doctors as would be a rapidly conducted AF condition.  While I can completely understand this (suffering from AF with a rapid ventricular response rate myself), the downside is that he was only offered a single lead to his right ventricle at the time of his implant in 2018.  With his loss of A-V synchrony, his AF has steadily worsened since implant and he is in AF almost always now with a subsequent decrease in cardiac output.  His RV pacing percentage has doubled since implant in 2018.  I will keep a close eye on his Ejection Fraction, since he has been diagnosed with right sided heart failure due pulmonary hypertension but single lead pacing in the Right Ventricle just hasn’t helped in my opinion.

The diagram of the conduction system in your new link is excellent. I always wanted to see it fully displayed like this - have been searching for an explanation of all the various pacing sites but a diagram does a much better job for me.  Now I know the area where my right ventricle lead is placed (right ventricular septal pacing) and from the diagram it is easier to understand the subtle differences in site position of the leads.  For example to know the lead positioning difference between Selective LBB pacing (which is the capture in the Left Bundle Branch alone, without capture of local myocardium) as opposed to Non Selective LBB pacing (simultaneous capture of the Left Bundle Branch and local left ventricular septal myocardium).  Now I need to fully understand when each lead position might best be used, although I see this question is still being hotly debated!  

I see that LBB pacing will result in a right bundle branch type morphology while HIS Bundle pacing is likely to have an advantage over LBB pacing in this regard by resynchronising RBB block.  Similarly, LBB pacing has advantage over HIS bundle pacing by being able to resynchronise LBB block (although the literature is apparently sparse).

FG, your posts have been an excellent way to start to learn about all the possible lead positions and pacing modalities available, our anatomy allowing of course, and how best to have that meaningful conversation with our doctors on this vast topic.  Thank you again for your persistence in seeking our views.  I have immensely enjoyed your threads and I hope you will keep them going in the future as new research and data from clinical trials are published.  I see that despite more than 20 years of progressively increasing experience of permanent HBP, several years of widespread global interest and uptake, there have been no long term large scale clinical outcome randomised controlled trials of conduction system pacing.  The HOPE HF trial was due to report in 2020 (or is still ongoing?)  Larger, long term studies comparing RVP, BVP and HBP will be required to fully assess LBB pacing outcomes.

FG-Excellent post

by Good Dog - 2022-08-20 09:57:52

This is an excellent paper. You are correct; I had referenced Dr. V (co-author here) in a recent post as an early advocate and sort-of pioneer in HBP. I had actually read this quite some time ago. There is a reference in this to the fact that physiological pacing has now been around for three decades. While that is true, in practicality, there was not wide-spread adoption until very, very recently. Somewhere back around 2014 I was prepared to drive some 370 miles for his advice when I could not find anyone locally to even discuss the possibility of HBP. At about that same time I read an article in which Dr. V was interviewed regarding the procedure and he said there was a significant reluctance to perform it at that time due to the difficulty and the time involved.

Additionally, if you consider that this was written several years ago, we have come a long way in just the last couple of years. As was mentioned, I think that references in this paper of the need for more dedicated equipment and greater operator experience, has to a significant extent already come to fruition. There will always be a need for more advances, more experience and more long-term research, but with the success rate for HBP being well beyond 90%, it seems that we are largely there. I also believe that there is sufficient evidence of the beneficial value to warrant wide-spread use of both HBP and LBBP. Currently, I have not read even so much as a hint of any negative outcomes from either procedure (O.K. none other than more rapid battery depletion from HBP).

FG, I commend you for your efforts to educate yourself so that you can be your strongest advocate for the best care. While I admittedly know very little about the technical details/aspects of these procedures, I can read and absorb at least enough to ask some pertinent questions and discuss the possibilities with my Doc in an effort to advocate for myself. I have enough faith and trust in my Doc to know that he will set me straight if necessary, and I will likely learn from that as well.

Sincerely,

Dave