ablation

[atrialfib]

can anyone tell me,the reasons why ablations dont always work,we are all human,all made the same,what are the reasons,someone said its because they dont know what to ablate and may get the wrong pathway,cant just be pot luck?

[SRMGrandma Volunteer]

Well, there are, as you say, lots of reasons. One certainly is that we all have different levels of disease at the time of ablation, and secondly, and maybe even more importantly, is, the level of skill of the EP doing the ablation. Another thing to consider is the general health of the individual, in addition to having AF or A Flutter. If they have underlying heart disease, or other systemic illness, they may be more likely to go back into AF again. Last but not least, if one has an ablation without changing lifestyle, then the AF will almost surely come back. The odds are much higher for long term success for those who embrace healthy eating, healthy exercise, good stress management and sleep both before and after ablation.

My ablation took 9 hours because of "very difficult anatomy" and in the hands of someone less skilled I may have had a less successful result, and if I had not switched to a plant based diet that has reversed my other issues such as high cholesterol, gerd, pre-diabetes, then I may be back in the same boat. Can an ablation still fail with everything being "perfect" ? Yeah, unfortunately, that's where the bad luck comes in. It is not a procedure with a 100% success rate.

[Beancounter Volunteer]

Hi atrialfib

Well not a medic, and never had an ablation but I'll try and explain as best I can.

In a heart in sinus rhythm (NSR) the electrical pathways run through two "nodes"

The SA (sino-atrail) node and the AV (atrio-ventricular) node when your heart is behaving itself, the SA node releases an electrical signal to the AV node which then tells the ventricle to pump blood (around the body and of course back to the lungs to re-oxygenate). The AV node tells the ventricle to sort of "re-charge" itself ready for the next beat.

This instructions come down pathways called Bundles left and right branch bundles.

When you are in AF the SA node simply does not not tell the AV node when it wants a beat and instead the electical stimulus goes on a roundabout path round the atria sometimes hitting the AV node, but often just going round in circles. The Atria while this is going on is beating like crazy often 150-170 or even higher, but the Ventria is sitting there waiting for its signal and not getting one. It does beat, but eventually and that beat can be slower or faster than normal, and often half hearted, so the full ventria does not empty and give a nice whoosh around the body, but sometimes only a 60% or 70% beat.

You might imagine that your normal electrics create pathways, and when you are in AF the rogue signals are creating new pathways and also some fibrosis, the longer you are in AF the more these pathways can become "normalised" and the more fibrosis can build up, which is why early and fast ablation is sometimes recommended as established pathways are harder to change.

So what a EP does when he does an ablation is try and map these electrical pathways, typically but not exclusively the area around the pulmonary veins is isolated either by freezing or burning to try and force the signal back to the correct pathway.

It's literallly different for everyone, each patient will be a new challenge to the EP to map the "wrong" pathways and try and force back to the correct ones.

So is it pot luck? No not at all, but it is so different from patient to patient, it's not an "on off switch" but testing and trying with each patient, with oodles of thousands of pounds of computer equipment looking at your heart while the EP does the ablation.

It's very complicated so unsurprisingly no real guarantees. But it is for many the only treatment we have.

Hope this helps

Be well

Ian

[atrialfib in reply to Beancounter]

Great stuff

[paulh1 in reply to Beancounter]

Great explanation Ian!!!

[BobD Volunteer]

I won't go into such detail as Beancounter but just to say that it is thought that the main rogue pathways enter via the four pulmonary veins. Hence ablation is often called PVI Pulmonary vein isolation. Cryo ablation is very good at isolating these areas due to the mechanics which I wont go into. right now. Sadly there are often other areas in the left atrium which fire off randomly which may later need to be ablated which is why some people have more than one ablation. The more complex the pattern of impulses the more it may take until either it is beaten or the EP decides that the heart has suffered enough and refuses to go again.

The second point is that some people are better healers than others. The purpose of the burns is to create scar tissue which can not pass electrical charges but if a patient heals too well then those scars will not be deep or cover enough and the ablation will fail.

At no point would I say there is any luck involved other than each of us' physiology.

[atrialfib in reply to BobD]

Thanks bob

[Peddling]

Wow! Chapeau guys. Thank you for your comprehensive explanations of what is for most of us, especially me, a very complex subject.

[Rellim296]

We are as varied on the inside as we are on the outside and hearts that work well can be far from uniform. Some 25% of us have only 3 pulmonary veins and some people have 5. I think too it's a bit like adding salt - EPs do as much as they think is needed and if it turns out it wasn't enough, more can be done. If they dive in too merrily, they might overdo things so they tend to be cautious.

[PeterWh]

There are very many factors and from what I have read it is less to do with what Ian says is the skills of the EP and much more down to the physiology of each individual. There will enviably be a difference between the very best and the worst but some of that will be down to experiences (not length of experience) of cases and someone new off he block can be better than another with 10 years experience. A lot of medicine is an art rather than an exact science or an exact engineering situation. The symptoms and affects of AF are very variable indeed as are the effects of medicines and interactions of medicines.

Relim says about the number of veins that enter the heart which is quite true. However the next key things are the size and shape of each vein in a single person. Where these are very odd or non standard this can make it hard, particularly with cryoablation, to make a good burn. As we all know different people can handle hot things but the temperature range can be quite high (ie one person can pick up a hot thing but the next can't). Even the same person can have differences between their right and left hands. Similarly from person to person the amount of energy that is required to ablate the cells varies (and after all unlike our hands the heart is not made to receive burns, hence why it gets very angry when ablated).

The advantage of cryoablation is that a single device makes a ring of (freeze) burns in one go so it is complete. With RF ablations the EP has to make a ring of many small burns around the entrance of each vein into the heart. If two adjacent ones are fractionally too far apart that potentially leaves a pathway for the rogue signals to continue to affect the heart's proper functioning. People with 3 pulmonary veins make it more difficult!!!

These days with RF ablations many EPs use a reduced power level to do the burns so as to reduce the chances of over burning and other complications. That does increase the chances of a subsequent ablation.

Another key aspect is not only "how good a person is at healing" but what their type of AF is and the duration taht they have had it. If people have paroxysmal AF then they have less pathways that conduct the signals. If they are in persistent AF they typically will have loads of pathways and some will have been firing for years this makes it harder to ablate them.

I am not medically qualified.

[atrialfib in reply to PeterWh]

you could have fooled me

[PeterWh in reply to atrialfib]

Fooled you about what?

[Jason71]

Wow, some great responses. I've copied and pasted all of them! I thought I knew a little about AF and these superb definitions prove just that, it was a little. Thanks all.

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Just reading the replies shows the value of being part of this fantastic forum!

[bluebird100]

I know this is an old thread but I wondered whether there was anyone out there who could help. I had my second ablation two weeks ago and had a 12 AF episode yesterday . My EP has told me he is certain now that my AF is not coming from the pulmonary veins but from the left had side of my heart. He is very worried about doing another ablation there as he said that there are a few vital nerves etc on that side and the risks are much higher if causing serious damage. I am feeling really disheartened by this and wondered if anyone else has been through this and could offer advice. My concerns are whether Is it now very unlikely that the third ablation will work? My EP was uncommitted on this and are the risks too high to have a third ablation. Be grateful for any advice.

[bluebird100 in reply to bluebird100]

And should say the right side not left side of my heart .. brain scattered

[bluebird100]

Sorry that should say 12 hour AF episode