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Atrial fibrillation and exercise: part 6: summary: what is AF, medications and medical interventions

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Atrial fibrillation and exercise: part 6: summary: what is AF, medications and medical interventions

Hi i’m steve selling the founder of the test a few people have asked me to put the main points into a summary presentation for atrial fibrillation and exercise so in part 6 of this video series on april febrile ation i have done that and really covered the topics around what is atrial fibrillation the commonly prescribed medications for growth and rhythm control

And also the interventions including the ablation therapies so first of all what is actual fibrillation let’s look at the normal heart first so in the normal heart the sinoatrial node or sinus node is the main pacemaker tissue this is the the tissue that drives both the rate and the rhythm of the heart and so it starts in the upper right atm or the upper right

Chamber and then it spreads you know a coordination fashion throughout the upper chambers and then a split second layer it then gets out down into the the bottom pumping chambers and the contraction in the upper chambers is responsible for about 20 percent of the filling of the lower chambers which means that the other 80% is just through a passing filling of

The lower chambers from the grapevines either coming from the venous system or coming from the lungs to fill the lift chambers and on ecg we see the atrial contractions shown here in the small p waves and then these largest spike spikes here that are in rhythm other ventricular contractions the contractions are the lower pumping chambers which dominate and so in

A normal sinus rhythm we have as this name suggests we have a consistent rhythm between or the distance between these ventricular spikes giving us with middle and a rate of about 60 or 70 at rest you know till fibrillation what occurs is that the atria become electrically chaotic in the sense that the there are wavelets of electricity occurring all over the atria

And it essentially electrically knocks out the sinus node so the sinus node can no longer do its job to control the rate and rhythm of the upper chambers and therefore of the whole heart and so we have this chaos occurring in the upper chambers and it random intervals and you can’t see it on this diagram but there’s another pacemaker cluster about here called the

Atrioventricular node and this act is an elliptical gateway into the bottom pumping chambers the ventricles and it controls what comes through from the atria into the pumping chambers below now when we have this chaos of atrial fibrillation at random times so not in rhythm that random times the electrical activity hits up against the atrioventricular node and then

Gets into the ventricles and we end up with an arrhythmia or a rhythm out of out of out of rhythm in the ventricles and that’s shown very clearly here on the ecg so the two features of the ecg that you can see in this situation of atrial fibrillation is we have fibrillation along the baseline which is really reflecting the these chaotic wavelets that occurring in

The atria and we have the ventricles that are out of rhythm here shown here because of the random times in which these and this electrical activity can get into the ventricles now what one of the problems then without your fibrillation well before i get on to though is just one other a brief comment and that is i’ve already said that over here in the normal situation

About 20% of the filling of the ventricles occurs when this coordinated contraction here in the atrium we lose that in atrial fibrillation but the person is still very much alive because they still get 80% of the filling coming from just from the flow through the atria from the grapevines into the two pumping chambers the ventricles so this is not a deadly rhythm

By any means the person is alive and relatively well although it’s some certainly not ideal but they get about 80% and they can actually still exercise quite successfully using other means that we’ll talk about in other other videos in this series so coming to the problem is because the atria are sitting there almost shivering shimmering like a jellyfish with not

Coordinated contraction it means that a blood clot can form and i’m just illustrated here a blood clot forming in the upper left chamber didn’t live talk to him if that blood clot was to get through the heart and into the blood vessel supplying the brain this could cause a stroke and in fact it’s one of the most common reasons common causes of stroke in australia

In 2020 the heart can also be too fast making exercise potentially unsafe and this is again because we have this chaos occurring here and if the atrioventricular node which is not showing here but acting is a bit of a break on heart rate if this leads to many of this electrical activity through the heart rate will be very fast and one of the prime medications

That are given to control rate of beta blockers which work at the atrioventricular node to just slow down the amount of conduction through into the ventricles so in exercise you know people with atrial fibrillation can exercise but my strong recommendation is those clients need to consult with a clinical exercise professional such as an exercise physiologist or

A physiotherapist now just going on with what a blood clot can do and how we can protect all our cardiologists and general practitioners protect against this is one a class of drugs given is an oral anticoagulant and in modern medicine the three or the the classes of drugs are most commonly given others are bands the x a bands which is really it’s an easy way to

Remember it because it blocks factor 10a in the enzymatic cascade for the formation of thrombin which is a critical step in the blood clotting process and a blocks factor 10 oh so x a band it’s a really easy way to remember it and then we have the trade names in brackets of these xa bands or the sour bands the most far most commonly prescribed drug is rivaroxaban

Or xarelto and then it next would be a pixabay anoi eliquis now there’s another class of drugs here dabigatran or pradaxa which is the direct thrombin inhibitor right at the end of the thrombogenic enzymatic pathway and that is also quite commonly prescribed if someone has a valvular atrial fibrillation they normally need to stay on quite an old drug which was

Prescribed widely before these oral anticoagulants became commonly prescribed and warfarin the problem with warfarin although it has to be given for valve lraf and it is a vitamin k antagonist the problem with it is that it has a relatively narrow therapeutic band which means too little and the patient will clot and too much and the patient will bleed and there’s

Quite a narrow therapeutic range there and so they have to have their blood levels of warfarin regulate mountain now if someone is in permanent or long-standing atrial fibrillation the the critical thing here is that the heart can be too fast and making exercise potentially unsafe and these and so what you need to be looking for as an exercise that professional

Here’s a navy known or inhibitor which is that other node supplying the the ventricles the bottom pumping chambers and what you’re going to be really looking for a beta blockers primarily and the three-month main video blockers which are given to control rate heart rate in people with permanent or long standing atrial fibrillation or a 10 along the top level

And so dalal and you will see so to long come up another couple of times in this video so these are the first-line drugs from rate control you know true fibrillation and but there are other alternatives that can be given to and that’s the calcium channel blockers which are basically member-owned stabilizers in terms of electrical stabilisation the two main drugs

Been heavy load around and soda law and the third main drug i want to alert you to is digoxin or lenoks and this is a and has one of its action tiers it blocks the av node to slow down the conduction through the av node now i want to just i haven’t touched yet on the anti-arrhythmic medications now these are given with the aim to actually use these medications to

Get someone back into or maintain sinus rhythm in people who are susceptible to out your fibrillation and the two mon drugs here again appearing as we have in the previous slide but for different purpose the calcium channel blockers hemiola and so too long so on the previous slide i made the point that these can control heart rate but they also have the ability

To control heart rhythm by maintaining membrane and stability now another class of drugs flickin id which i’m not going to talk about my because it’s not i don’t come across very often in my practice it has real problems for people with heart failure or other heart problems this will be very tightly controlled in its prescription and to be honest i very rarely

See clients who are on flick a night but i’ve just mentioned it here as an anti-arrhythmic now i’m just going to go back over those heart rate controlling medications that were on the previous slide very quickly the beta blockers tender longs at the top along soda law notice then you will end in lol as you remember tell some channel blockers come up again maybe

Neural blocker comes up again and now want to move on to another intervention to try and get someone back into rhythm sinus rhythm normal rhythm is cardioversion which is an elective defibrillation given on their own aesthetic and this is the hope with this is that this will shock the heart or the atria the upper chambers back into rhythm the success rate is is

Reasonable on first and second application of this but the long-term the the long-term success with this is probably a little less so we now move on to one of the really common modern interventions used for atrial fibrillation and the first one of these is one there’s a group together is ablation therapy an ablation basically is either applying cold or heat to

Create star tissue and in this first instance i’m going to talk about pulmonary vein isolation now here we can see – pulmonary vein insertions into the upper left chamber the left atrium coming back from the lungs and there are another two here where i’m pointing so altogether there are four put four pulmonary veins and what is done in the pulmonary vein ablation

Procedure is first of all they use diagnostic catheters to map the early rhythm years and then what is what is done is they then use blasian catheters to apply cold or heat to deliberately encircle the pulmonary veins with scar tissue which will then prevent the arrhythmia from escaping into the rest of the upper chambers the atrium chambers essentially isolates

The arrhythmia into these four small regions and then the silent electoral mode which is not shown here can then really dominate the rhythm of the atria and therefore the ventricles and the person is then effectively cured in a sense in terms of their arrhythmia although whatever underlying cause was responsible for the atrial fibrillation in the first place is

Not treated by this oblation technique so for instance if the atria still enlarge then they remain enlarged after the pulmonary vein isolation but they hopefully will be back into sinus rhythm and this has a fairly good success rate sometimes the pv eyes have to be repeated but overall it’s about a 70 to 80 percent success rate to maintain long-term rhythm in

People susceptible about girlfriend relation so that the next step technique i want to highlight is atrioventricular nodal ablation and i just mentioned atrial enlargement and some of the patients who have very enlarged atria and not they don’t have a great success rate with a pulmonary vein isolation and so another technique can be used and in this situation the

Ablation is applied to an otherwise healthy atrioventricular node in this region of the heart here which normally drives the rhythm of the ventricles so what we do what’s happening in atrioventricular nodal ablation is that this is knocked out and so effectively the atria and the ventricles are electrically isolated or separated so that whatever rhythm remains in

The atria which in this case will be able to live elation is actually not it cannot then get into the the bottle and pumpkin chambers the ventricles because the atrioventricular node which is the controlling if you like the electrical filter into the pollen chambers is now knocked out and there’s an effectively an electrical separation of the fibrillation going on

Here and what will now be a rhythm however in this situation a permanent pacemaker must be fitted and i’ve illustrated that in one of my case studies in this series so if this av nodal ablation is applied normally what happens is a pacemaker must be fitted either at that time or before that procedure is conducted in the same session so that the ventricles are then

Pasted in rhythm otherwise this would be obviously dangerous because the ventricles would have to generate their own rhythm which could be quite unsafe so just to summarize atrial ventricular ablation electrically separates the upper chambers which continue in atrial fibrillation so we’re not a blazing the pulmonary veins or any other part of the atria there ablating

This otherwise healthy tissue electrically separating out through and ventricles and the ventricles must then need to be post and this is shown down here quite nicely this is one of my clients who had this atrioventricular nodal ablation and i’ve given you this in another case study so you can watch that other video in a pre exercise you can clearly see the atrial

Fibrillation in the baseline of v1 which sits over the right atrium and so it can pick up the atrial fibrillation that is still existing but in both of these leads v5 sitting over the left ventricle you can clearly see that the heart is now in rhythm even though atrial fibrillation continues the heart is now in rhythm and that’s a really good outcome and you can

Also control the rates really well as well so in peak exercise again you can see the fibrillation occurring or persisting in v1 and also in you can see a little bit of it in 35 but the heart peak exercise remains in rhythm with good rate control so we’ve got a really good outcome there so that’s what i wanted to do to summarize for you some of the main concepts

That i was talking about for a peeled fruit relation for exercise professionals because people wanted a sort of a summary video and that’s what i’ve done here and if you want to contact me about this or anything else info at my fitness combo you so have a great day and i look forward to sharing more cardiac physiology especially for exercise professionals in in other videos bye for now

Transcribed from video
Atrial fibrillation and exercise: part 6: summary: what is AF, medications and medical interventions By Steve Selig