Hello, and welcome to this session on bovine cardiology. I'm really excited to be giving this talk for the webinar vet. It's a topic really close to my heart, and I'm hoping that we can, talk about some of the diseases lots of us see in cattle all the time, and also talk to you about some of the, some of the challenges in other parts of the world that relate to, the bovine heart.
So I don't have any disclosures relating to this presentation, but I thought I would introduce these two cows. And they, I suppose, really got me into the, to the bug and wanting to be so much better at bovine hearts than I was. So the cow on the right, who I'm gonna show you some of her images later on in this talk.
Her name was Valentine and she presented. To, to me when she was about 12 weeks old for a hernia repair and had got a loud left and right sided murmur. And she actually came and lived with us as a teaching cow first at the Royal Veterinary College and then at the University of Nottingham and lived with us till she was a grand age of, 8 years old.
She taught many thousands of students about bovine and cardiac auscultation. And then the cow on the left, his name was 6 pints. And I suppose he was the one that beat me.
He was about a 1200 kilogramme South Devon Bull, and I just couldn't get any cardiac images on him, however. Hard I tried and whatever ultrasound machine I used. So, he was, he was very patient whilst we, whilst I did my very best to see whether or not I could get some, get some images when he was a, a patient at the RVC.
So, let me tell you about the the setup for this talk. So I'm gonna start off by talking to you about doing echo in the cow and what the value can be to both you and the farmers. And we're gonna talk about the sorts of images that you can get with your Easy scan, usually in late pregnant.
Mode. And also, you know, some of the cool images that you can get if you have access to a machine that does, that you might use for sheep PDs, for example. And many of the images I'm going to show in this talk, you would be able to get with those, with those sort of sector pro to use for PD and sheep.
And then we're gonna concentrate on, you know, on the groups of diseases that we see. So, we've got endocarditis, myocarditis, pericarditis, and we're gonna talk about some of the options for the management of pericarditis in terms of salvage procedures, particularly if we're trying to get cows to, to calf. Then we're gonna have a think about some congenital cardiac diseases, and within that, I've certainly got an example of, of valvular disease.
We, we generally don't see primary valvular disease, but we do sometimes see it, as either a consequence or because of congenital disease. And then we're gonna have a think about some dysrhythmias, that we do come across in, in. Cattle.
And then I'm going to finish the talk talking about some of the challenges of, managing cattle at high altitude. And that's done quite a lot in lots of parts of the, the world. And I'm going to show you some, a study that I was involved in many years ago, and, and some of those challenges that, that, bovine vets and, and ranchers certainly face.
So let's start with thinking about echocardiography. And the one thing I would say is that cattle are actually very amenable to having their hearts scanned, largely, both dairy and beef. And if you can stand them somewhere that's not in an AI stall, they will usually be pretty helpful and stand with their limbs forward or out to the side.
And the reason why that becomes important. Is the cow's heart is a long way underneath its forelimbs when we compare it to dogs, cats, and, and horses. And here you can see this is a picture taken from quite a long time ago with a big hospital machine.
And this cow's, you know, standing, having a heart scanned and, you know, with these hospital machines, we can get some great images as long as the beast isn't, you know, 1000 kilogrammes. But many of you aren't gonna have big hospital machines or fancy ultrasound machines that you can have a 30 centimetre screen and you can image, you know, the whole heart. So, the bits of advice that I would give you is, use the best ultrasound machine you've got access to, and you're gonna want to use the lowest frequency, either probe or setting that you have on your machine.
Now, these sheep PD machines have often got Sector probes that are running at 2.5, 34 MHz. And you can get some really good images on your, on those, on those machines.
But if, if you've only got an easy scan, you actually can still visualise some of the heart, particularly in late pregnancy mode. And if you look on the left and right sides, I'm gonna show you what the sorts of images that you will be able to get, you should be able to diagnose. Right sided endocarditis and pericarditis pretty easily.
Myocarditis a little bit trickier and as can some of the congenital heart conditions be. And when you're coming to get these, these images, you always need to be a bit higher up and a lot further forward than you, than you think you should. And you're only gonna be able to, to image the heart in one plane, and usually in long axis, running your, Running your rectal probe along that rib space.
But even so, you can still get some pretty good pictures. And the reason I think bovine cardiology has never taken off, really, with even with people that do have access to some of these better machines, is it's actually pretty hard work. So, this is a picture taken from Sisson from a long time ago, that I've sort of moved a little bit and, and, and sort of altered.
But this is the sort of, image that you can get of the heart when you're scanning from the right hand side. And the right hand side, largely is gonna be, is where conventionally, we get. Most of our images from, but it's certainly the side you're going to want to concentrate on, especially if you're looking for, endocarditis or, or pericarditis, lesions.
So what we've got here is we've got the, we've got the right atrium, we've got the tricuspid valve, and we've got the right ventricle. And then we've got the interventricular septum. Now, if you're using your I scan, that's probably What you're gonna be able to see from the left-hand side.
If you do have, access to lower frequency, maybe some sector or convex probes, then you're gonna be able to pick up this left ventricle at the bottom. This is the mitral valve and the left atrium. And then we've got the aorta here.
And we'll, sometimes we'll pick that aorta up, depending what angle we're cutting through the heart at. And if you do have access to those, to, to perhaps one of those PD machines, you will be able to rotate your image and look at the heart in, in short axis, and then you're able to chop through the valves in, in cross sections. So here in this picture, we've got, we've got the, the tricuspid valve at the top, we've got the mitral valve at the bottom, and then we've got the aortic and pulmonary valves in the middle of the screen.
So, this is an image taken, and this is with a microconvex probe, but it's the sort of picture that I would expect you to be able to get on your Easy scans in late pregnancy mode. And here on the right hand side, we've got the, we've got the, the right atrium. And then in the middle of the screen, we've got the tricuspid valve, and then to the left, we've got the .
We've got the right ventricle. And you can see, we can see the heart muscle of this right ventricular free wall. It's pumping pretty hard.
And between the heart and the probe, we've got some skin and we've got some intercostal muscle, but you can see there's nothing really between the muscle and then the muscle of the heart for us to be concerned about. And then when we move a little bit lower down into the picture, we start to pick up that interventricular septum. This is a very similar image, but this is taken from the left hand side.
And so again, that sort of image you're gonna be able to get with your E scan. So this time, because we're on the left, the focus is gonna be, left atrium is gonna be in the bottom of the, the picture. Then we've got the mitral valve, and then we've got the left ventricle.
And again, down at the bottom of this image, we're just picking up that interventricular septum. And again, most importantly, if we're thinking about myocarditis, you can see that heart muscle's pumping and working really hard, and we've got muscle and heart muscle sitting side by side, and obviously they'd be pushed apart if we had a pericardial effusion. Now, when we're looking for pericardial effusions, sorry, I'll just have to excuse me a minute for switching my pointer off, when we're looking for pericardial effusions, sometimes the easiest place to be able to see that is actually quite low down, either on the left or right sides.
So what you can see here, if you looked a little bit more caddal, you'd have plural surface and you'd be in that region where you might be looking. For, you might be looking for, bovine respiratory disease type lesions, consolidated lung in that cranio ventral quadrant. And then if we look a little bit further forwards, what we're able to see is the apex.
And obviously, that's gonna be the right apex on the right, and it's gonna be the left, cardiac apex on the, on the left. And, but again, what you can see here is we've got We've got skin, we've got muscle, and then we've got, we've got the, the heart. So, again, if we'd got a pericardial effusion, we'd start to see fluid in between the intercostal muscle and the heart muscle.
Just got to switch my laser pointer off again, sorry. And this is a, this is an image that we, you know, is often seen as being pretty old school now, this is taken on a, on a bigger machine where we're down at a sort of 25 centimetre screen depth, and this is just an image showing a plot across the, the left and right ventricles and looking how they move over time. And so what we've got here.
Is we've got the right heart at the top, and then we've got the interventricular septum in the middle, we've got the free wall at the bottom. And then this here is the right ventricle, and this here is the left ventricle. And you can see that that left and right side of the heart are beating at the same time, and that we, we can see what our fractional shortening is.
So, this can be a really useful view if we're starting to worry that we might have disease of the heart muscle itself. We've got some form of myocardial dysfunction or myocarditis. So what I thought I would do is now I will talk to you about some of the cases, show you some of the images that we've got, and we'll try and explain those images as we, as we go through.
So this was a 3 year old Holstein Friesian cow that presented in lots of, you know, as many of these cases do to us, presented with, just not doing right, decreased milk production, tachycardic. She had reduced ruminal contractility and, nothing really had, had come up on any of the other evaluations that we had done. And this was the image that we got.
I obviously went looking for more common things being common. And hopefully, what you can see in this picture, this is a, a long axis view focused on the right side of the heart. And what we've got in this image is we've got the right atrium, sort of top and Top right, we've got the tricuspid valve, and then hopefully you can see we've got this vegetation sitting within the right ventricle.
Now, lots of people and we always say to you, well, you know, normally when you've got an endocarditis lesion, you're gonna have a cardiac murmur. And that isn't actually true. Only 40% of animals that have Got endocarditis, have have murmurs.
One of the most reliable measures of a likelihood of endocarditis is increases in, acute phase proteins, be that fibrinogen or serum amyloid A. The challenge for us as cattle vets is lots and lots of diseases that cattle get show an increase in fibrinogen concentration. And this was one of those cows where, lots of money had been in inverted commas, wasted trying to fix this cow by treating it in a, in a sort of symptomatic way.
And you'll see that, you know, the, the interesting part with this, with this animal is, this is its pulmonary valve that you can see in the top part of this picture. It does have a very small, endocarditis lesion right on the. On the cusp of that pulmonary valve, but in fact the biggest vegetation was sitting within that right ventricle, which is perhaps why, you know, this is one of those animals that didn't have a really loud cardiac murmur.
And these are, these are not fixable, these cases. So, you know, in terms of thinking about why you would do this, really it stops the farmer wasting any more money on yet another different course of antibiotics and anti-inflammy. Because this animal is not gonna get better and it's likely that bits of that endocardial lesion are gonna seed off usually ending up in the lungs, resulting in pulmonary abscessation and a a pretty sick cow.
So, the next case is a 3 year old Holstein Friesian, and she had a history, approximately 3 weeks previously, of being pyrexic and having laboured breathing. She then recovered, she had again a course of anti-inflammatories and. Antibiotics and she'd improved, and then she represented with, tachycardia and a decreased milk production.
And heart rate was probably around 120, beats per minute. She did have variable jugular filling on physical exam. And again, slightly quiet, you know, her room and turnover was certainly reduced.
And this was what her echo looked like. And again, this wasn't the first thing that we did with this cow. It was one of those things that we sort of got to when we hadn't found anything else.
And this is what we would regard as a sort of modified for chamber view of the heart. So, again, it's a long axis view of. Heart taken from the right hand side, where we've got the right atrium in that top right hand part of the picture.
We've then got the tricuspid valve, and then we've got the right ventricle over and over to the left. And then at the bottom of the picture, we've got the left ventricle, the mitral valve, and the left atrium. And hopefully, what you can See from this is, and this image, this, sorry, this, echo is slowed down so that you can really look at how the heart's contracting.
But, you know, for the fact that this cow had got a pretty high heart rate, the heart really wasn't doing very much. So it looked like it was certainly not contracting as hard as we would have liked. And what we did was we rotated because I had a more of a sector type probe to evaluate this cow, rotated that probe so that we could look at the heart in short axis.
And what we've got here is we've got the right side of the heart at the top of the image wrapping around this sort of mushroom shape. Which is the left ventricle. But when we look at the image at the bottom, which is this M mode, plotting what that left ventricle is doing over time, you know, you can see that actually, that heart really isn't doing very much.
It's really not contracting very much at all. And it's very difficult to diagnose myocarditis. So, on a, on biochemistry, you might see increases in, in enzymatic, activities of creatine kinase.
And we can measure cardiac troponin in cattle in the same way that we can measure it in horses. And this cow did have an increased cardiac troponin in. In fact, her biochemistry, her CK was, was normal.
So, we made a very tentative diagnosis of myocarditis. And myocarditis is a really tricky thing because it can end up being secondary to a whole bunch of different diseases. So, anything from some forms of, ionophore toxicity.
Which we'll occasionally see if someone's got concentrations wrong or have been put inappropriately into a wrong feed types. But we can also see it's secondary to viral and bacterial infections. And interestingly, you know, one of the reasons why foot and mouth disease, when it's endemic in countries, leads to such poor productivity is because many of those animals have got a myocardial dysfunction.
And in terms of treatment, often it just requires some time. So some people have tried using steroids to see whether that will dampen down the inflammatory response. But, you know, as the history gave you in this cow, this cow was probably sick with something several weeks ago that has sort of gone and it's left with post-viral or post bacterial accele, which in this case has manifested as.
A potential myocarditis. And these cases, often, if you give them some time, will actually come right. And by time, we're not always talking months or years.
We're sometimes talking just, a few weeks. So, they aren't necessarily, although they will often initially present looking like they're in heart failure, they can often, recover and sometimes recover fully and, and go back to normal. And then the next case, again, it's a 3 year old Holstein Friesian, and it's 4 weeks from carving.
And this was a pretty sick cow. And she was tachycardic and she had distended jugular veins. And interestingly, when I show you these pictures, you'll be like, Well, you didn't need neck.
To tell that this animal had got a pericarditis. But in fact, this cow did not have washing machine noises when you were auscultating her heart. I suppose what I would say is, her heart just sounded pretty quiet, although she, she wasn't the smallest beast in the world to, to auscultate.
And when you come to thinking about pericarditis, I think one of the interesting things with, with cattle is that it can, I mean, it's obviously usually secondary to a wire, although it doesn't have to be. But that Actually, there are different options that you might want to try if you've got an individual valuable animal or you're trying to, you know, in this case, the farmer wanted to salvage this cow, see if we could keep this cow alive until until she calved. And so what's interesting when you look at this video, is you can see that this, that this heart is actually working quite hard.
But what's cool to notice is it's still actually pretty fluid. So, you know, sometimes these pericarditis, they set like cream cheese, and they become really, really restrictive. And you can see it's got this bright white edge on this pericardium, suggesting that we've probably got some fibrin sitting in there, which is not not a big surprise to us when we're, when we're contemplating.
Cattle that have got, that have got a wire going into their, into their pericardium. This is that same cow, and hopefully you can see that heart's just not working brilliantly, which is not a surprise because it's got lots and lots of fluid around it. So where this farmer was concerned, the farmer wanted to know, you know, what did we think we could do in order to get this cow to calving, and we had a pretty good idea.
This farm had a lot of problems with wire related disease, so we knew it was likely gonna be a wire and common things are common. So the options that I gave this farmer, because that fluid is still pretty liquid, was, we could try drain and lavage, and, you know, that was something that we could probably repeat. We could drain and lavage and try and put, some non-irritant antimicrobial into the, into the pericardial sac.
That can be a little bit. More challenging with antibiotics that we have available. We talked about whether we just tried systemic antibiotics to see if we could at least dampen down the bacterial load and reduce how much more fluid was produced.
And then the last option, which I certainly have done once or twice, was to offer to do a pericardectomy. And this was a technique that was described many, many decades ago in cattle. You do it standing, but you do have to do a partial rib resection, in order to gain access to the pericardium, and then you make a window in the pericardium, you scoop out or wash out all of the crap, and then you close the muscle and the skin, and then the fluid.
That that would have been in the pericardial sac will then drain into the, into the pleura and be better managed. Again, it's a salvage procedure and it does give you the opportunity if the wire is still in the pericardia to, to remove that wire as well. It's certainly pretty hard work to do, but it, it certainly, it can be done, like I say, is described in the literature.
So what we did with this case, in fact, was we did drain and lavage. So we put a cannula from the right hand side into the, into the pericardium that we did under ultrasound guidance, and we drained out as much of the, of the fluid as we could, and then we flushed it through with a few litres of saline done in a sterile manner. And then we said, We'd see how long it took to refill.
And actually this cow ended up only being drained once, and she got to she got to calve, she had a pretty healthy, she had a healthy calf. And then about 7 daysish after calving, she again presented with signs consistent with heart failure and we euthanasia at that point. She did have a heifer, so everyone was pleased.
So this is another case that we had. This was not wire related, which we obviously didn't realise at the, at the time. And again, using ultrasound, it just gave us an idea, this, this steer presented with.
Tachycardia. He had his neck outstretched, he had his elbows abducted, looking, in fact, like he'd got, as much got cardiac disease as respiratory disease. We didn't find any abnormalities, particularly when we, did further evaluation of his respiratory tract.
But when we came to scan his heart, hopefully you can see here, we've got skin, we've got intercostal muscle, and then we've got fluid between those intercostal muscles and between the heart muscle. These are the ventricles sitting down here. And again, this fluid here is pretty clear.
So it's not always easy to know why these animals, if they aren't wire related, have got a pericardial effusion, but certainly in other species, which we're gonna come to in a minute, we can see these very occasionally with vasculitis related to to herpes. So, this was, an effusion. We actually, we drained it, we treated the steel with anti-inflammatories, and in fact, that effusion never came back.
His clinical signs resolved, he went back to the, went back to the herd. Oh, sorry, there you go, can see that moving. But you can see one of the reasons why this, this animal was quite so, tachycardic.
Really wobbly, really wobbly hearts, not, not showing true, true contractility of either of the ventricles. And I said I was going to talk about some other species. We don't always get beautiful quality images in cattle.
This is actually an image taken from a young elephant that weighed about 600 kg. This elephant presented depressed. Of suck with pyrexia, and on, he did have washing machine sounds over his heart.
And hopefully, what you can see here, again, we've got very thick skin for an elephant. We've got intercostal muscle. We've got the ventricular, this is the, right ventricular heart muscle sitting here.
And then we've got this effusion, and sadly, pericardial effusions in in elephants have been linked to, have been linked to elephantine herpes virus and they are, they're having a 90% mortality rates. And so we, again, he was in heart failure, we drained, we drained this, . As you can imagine, with many elephants that are kept in captivity, money was no object, antivirals were were were used as were anti-inflammatories, and this, but this refilled, several.
This refilled within sort of 48 hours. If you just, I'll try and play that video again for you, sorry. But hopefully, what you can see now is this has really become restrictive.
So that heart muscle, the heart's really not moving very well, and what had been quite fluidy, sitting within that pericardial sac has become much, much more organised and, and solid. And sadly, as with many of these herpes virus cases in elephants, this, this one didn't, didn't sadly make it. And just to remind you, from what I said at the beginning, the very best place to diagnose a pericardial fusion is really low down where you can, you can really look at the apex of the heart, either from the left or the right hand sides, and you're looking to see if you've got fluid between that intercostal muscle and the heart muscle.
And we've talked about this already. I mean, I would say, more commonly than that first cow that I presented to you that had actually got quite a fluidy pericardial effusion. Many cattle by the time they present, particularly with, you know, an infectious pericarditis.
To a wire, they've actually got cream cheese, you know, it's set, sitting in their pericardial sack. And with, when that's the case, most of the, you know, the best thing that you can do with those animals is, save the farmers' money by not. Going forward with any further treatments and to and to euthanize them, but certainly working out whether you've got something solid or something fluid, you're gonna be able to hopefully offer, give you, give different give different options to them.
OK, so, the next case I'm gonna talk to you about is, is this 9 month old, limousine steer that looks pretty crappy. He's got a failure, he presented with a failure to thrive, he was pretty quiet, and he had been treated, initially for intermittent, bloating. And you can see he's in pretty poor body condition and he's got quite a lot of, of edoema and that.
Edoema ran really from the pectoral region all the way up to his jaw. Now I've just got some more close up pictures of that, just showing that pitting edoema, really hard to know if he'd got distended jugular veins. But what was interesting on his physical exam was he had got really hyper resonant lung sounds dorsally.
Really dull lung sounds ventrally and you could auscultate his heart in about the 8th intercostal space. So you had some idea there was something weird going on in this animal's chest. So although initially he'd presented.
A sort of a GI type workup, and it looked like probably the GI presentation was secondary to something going on in the thorax, perhaps, perhaps having some impact on the, on the function of the vagal nerve. And I'm afraid I don't have his echo. His echo was really cool and unfortunately the, the, the video is corrupt, but I thought I'd tell you about him anyway.
So this is actually an X-ray that we've got, and it's an X-ray of a thorax rather than of a heart. But what you can hopefully see here is we've got sort of lung, and we've got the ribs coming down here, and then we've got what looks like this really big capsule that we've got sitting here, and then you can see based on this X-ray, we've got a plural effusion. This is an image further forwards, I'll try and orientate you, you've got the scapular here and the humerus here, and what should be rocking up in here is the heart, we just couldn't really see.
Now I grant you it's not the most beautiful X-ray that I've ever taken, but but it didn't look like it was in the right spots. And then when we started imaging his lungs, you started to get some really abnormal pictures. You know, normally you would have that plural surface with a glide sign moving forwards and backwards, and we were starting to see all sorts of funky stuff in this, in this beast.
So, you can never say that you've got an abscess on ultrasound, but this certainly looked like some form of spherical lesion with a, with a hypoechoic centre to it. And here we've got the plural surface sitting here. And so this is the parietal pleura, this is the visceral pleura, and we look like we've got some stuff in between.
And if I'd got the echo to show you, it would show that the heart was really, really small, moving in a really weird way, and had got a, again, had got a pericardial effusion. This is just some more stuff, sitting in that plural space. Anyway, treatment for this, this beast was, was not very successful, as I'm sure many of you can imagine.
And we got a wire again in this case, we've got this massive plural abscess that had, actually eroded. The wire hadn't gone into. The pericardial sac, but we just look like, you know, we've got erosion, sort of, thinning and even some small holes in the surface of that pericardium that were found histopathologically.
And the pus was also sitting in front, in front of the heart as well as behind, and it was sort of pushing the heart caudal. OK, so now I'm gonna move on in the next part of this talk, to talk about congenital cardiac disease. And right at the beginning of this talk, I, I introduced Valentine to you.
She was named by the RVC students a very long time ago. And she presented as a 12 week old heifer with, loud bilateral systolic murmurs, and when she presented for a, for a hernia repair. And that she came from a high yielding herd, relatively close to the Royal Veterinary College at the time, and we spent a long time deciding whether or not this was an animal that, A, we should keep, keep as a.
As breeding stock, but also whether or not we thought she would cope with the stress and strains of pregnancy and milk production. And there isn't actually lots of data available to know whether that was going to be the case. But I'm gonna show you some of her images and she she stayed with me from 12 weeks of age until she was until she was nearly 9, so she, like I said, she taught a lot of, a lot of students about bovine cardiac auscultation.
So, I'll try and, I'll try and orientate you with some of these images. So what we've got here, this is a view taken from the right hand sides, we've got the right side of the heart at the top. We've got the interventricular septum.
This here is the aortic valve, and hopefully what you can see is that there's a hole in this interventricular septum. And this was a perimembranous subbiortic ventricular septal defect, very similar to what we would, what we would see in in horses. And the, she had, when she was young, she had a bilateral systolic murmur.
So the right-sided systolic murmur is all to do with turbulent blood flow, with the blood that's flowing from the left side of the heart to the right. And then the left-sided murmur that we get is all to do with extra blood flow that's entering that pulmonary artery. So, that was her, that was her, That was her her defect and hopefully you can see that defect here in this moving image from a time when she was perhaps a little bit younger.
Now, she developed a a secondary complication, so when she got to about 2, we started to be able to hear a diastolic murmur as well as the two systolic murmurs that were associated with her ventricular septal defect. And the reason this diastolic murmur developed was because one of the cusps of the aortic valve was getting sucked into the ventricular septal defect, leading to that aortic valve leaking. And although it's not that well described in cattle, we know that this happens in probably 5 to 10% of horses that have ventricular septal defects.
And this is just an, an image. This is the aorta in cross sections, so it should be showing you a sort of Mercedes-Benz symbol of those three cusps of the aortic valve. And here is one of those cusps getting socked into the hole that sits here in the interventricular septum.
And then this is the image just highlighting with colour flow Doppler, the size and position of that of that VSD. And so the reasons that we thought about, you know, where we should go in terms of her of her staying in a milking herd were we know in, in horses that. Ventricular septal defects, even when they're small, can reduce, performance, and everyone that, Was knowing about ventricular septal defects in other species, was just concerned that maybe flow would increase through that VSD and cause further problems in that time, sort of late pregnancy in those 1st 6 weeks of lactation, where we know cardiac output can increase significantly in, in cattle.
And eventually, Her demise was due to her ventricular septal defect. And I'm just gonna go back to one of the earlier pictures to show you, to show you, I suppose, what we thought was the start. So, we know that the blood goes from the left ventricle into the right ventricle, and it can end up that that jet of blood as it enters the right ventricle, can damage one of the cusps of the tricuspid valve.
Or it can start to cause thickening or changes within the inside surface of the right ventricle and. This really thick structure that you can see here in the top left hand part of the picture is in fact a moderator band that's become really, really thick. And it's something that we pick up, not uncommonly in animals that have got VSDs.
Anyway, when she got to approximately 9 years of age, she was found one day, not looking very well, tachycardic. She was recumbent, and didn't have a cardiac murmur. And again, cardiologist was, was called in and on echo, she'd actually developed tricuspid valve endocarditis, and endocarditis within in.
Inside that right ventricle. And it's almost certainly that that endocarditis was secondary to, to some jet lesions that will have been going on for a period of time. And then obviously she'll have been challenged by some form of infection, and we'll end up, end up where she was.
And at that point, she was, she was obviously euthanized. So the next one, was a 2 year old, Holstein Friesian. Again, she presented with lethargy and tachycardia.
And it was a, it was a tricky old case, really, that there was nothing much to find other than this tachycardia. And what you can see in this image is, I'll see if I can get that to play again. One second.
Is this now is a, is an image of the, this is the right atrium at the top, the left atrium at the bottom, and hopefully you can appreciate that we've got blood flowing between the atria. So this is an animal that's got an intra-attrial septal defect or an, a, a, an atrial. Septal defect.
Now they aren't normally associated with cardiac murmurs. We do know from postmortem studies, they're quite common in cattle, and they're largely regarded as incidental findings. I mean, this one was probably about 2.5 centimetres across.
And this is, this is some, I, I, yeah right. This is this is. Hi, you all right?
This is, this is some 4D imaging of a, of an atrial septal defect, not actually taken from, from a cow, but a sort of similar, that's sort of showing that sort of similar lesion. And the interesting thing about atrial septal defects is they can actually be associated with some quite severe clinical signs in people, which include, migraines, they include stroke, they include sudden death. So we sort of are a bit, perhaps a bit blase about the significance of them when we find them in, in cattle.
But certainly, certainly we know that prevalence can be pretty, pretty high in, in cows with, with those. So, who knew whether that was the, the cause in that case? We were pretty sure it wasn't, but I thought it was an interesting thing to, to bring up and also about how common they are, and maybe we, maybe we overlook them.
So I've now got some cases that are a bit younger, that have presented and some of the reasons why the images are perhaps not very standard is because they don't have very standard hearts. So the first one was a 6 month old Holstein Frisian heifer that had a failure to thrive and grow and had got a cough. And this was on a farm where bovine respiratory disease was alive and well and certainly had a pretty high prevalence, and this was one of those animals that, I just kept moving down age groups until, you know, it was probably standing there and it looked like it was maybe 8 or 10 weeks old rather than 6 months old.
When you came to listen to this, to this animal, again it had a bilateral systolic murmur and. When we came to scan it, this was probably the best of the images that we got. Actually, very, very difficult, some of these congenital conditions to get really, really nice images.
So I'm going to try and put my laser pointer on and show you the bits that I thought it was. So this is an image that's been taken from the right hand side. So we've got the right ventricle, which is really, really big.
And we've got the left ventricle sitting at the bottom. And then we look like we've got a really, really big aortic valve, and it looks like both the left and the right ventricles are draining into this one big vessel. So this one big vessel should be, should be the aorta coming out of the left ventricle and the pulmonary artery coming out of the right ventricle.
Anyway, the, the farmers were very reluctant to, to, to euthanize this, this cow. They were very keen to see whether it might get better with some other magic drugs that we might think about. And I did try to explain that I probably could manage its heart failure, but I probably wasn't going to be able to fix the severe congenital abnormalities that we had got.
And eventually, it didn't get better over sort of 4 or 6 weeks. We, we did try this, we certainly treated this animal with some, with some rosemide. We don't have too many other drugs that we can use in food producing animals, cardiac wise.
And it improved for a little bit. It's cough got a bit better, and then it, it just, it just resorted back to where it had been before. And a postmortem examination.
This animal had got a tetralogy of fallow and what had happened congenitally was it's got a big interventricular septum. It's got this overriding aorta, but also that this big structure here that should have Be an aorta was a persistent trunkcus arteriosis, and the trunkcus arteriosis embryologically is the thing that should break, separate down into the pulmonary artery and the aorta. The next one was an eight week old Holstein heifer, that again had got a cough and failure to thrive, was also in a barn with with a group of, with a group of animals with bovine respiratory disease, and it had been treated with 3 different courses.
Of antibiotics and had not improved and it did indeed have consolidation in its cranio ventral lung globe on the, on the right, but this was it's the image that we got of its heart. And again, this is taken from the right hand side, so we've got. Right ventricles at the top.
Left ventricles at the bottom. We've got the tricuspid valve, and we've got the, right atrium, left atrium, and the mitral valve. And hopefully, what you can see here is it's got some double apexing of the, of the heart.
And this right ventricle's really, really big. So, it's then trying to work out why has it got a big right ventricle. And in fact, when we got a nice close up picture of it, hopefully you You can see that this, animal, for want of a better word, has got a pretty knackered tricuspid valve.
So, its tricuspid valve was just dysfunctional. It's probably dysplastic in a, in an animal of this age. It's less likely to be, an endocarditis lesion.
The alternative of what might have happened with this animal is that actually some of the corer tendon that would normally support that tricuspid valve had, had ruptured. And then we had had another calf, actually from a very, a similar group, again, group that we were evaluating for bovine respiratory disease, again, another one, failure to thrive and a cough that had been non-responsive to antibiotics and. In this case, anti-inflammatories as well.
And again, hopefully, you can see, it's almost the same image that I showed you in the previous one, really, really big, really big right, right ventricle, sort of normal sized left ventricle, and that heart's working pretty hard. And in this case, we didn't really find any cardiac abnormalities to suggest why this animal had got such a big right ventricle, that this animal had got very, very severe respiratory disease. It got a lot of it's right lung, both, cranial and middle lung globes were consolidated.
And so we were. I wondered if this was secondary to a pulmonary hypertension, but obviously because it's starting to get these cardiac changes and its lung changes were very, very severe. And again, same as the previous two calves I've shown you, you know, the advice to the farmer in this case was, we probably needed to cut our losses, stop wasting our antimicrobials on these, on these cases.
So, just to finish off, I thought we'd, we'd sort of change location. And, many years ago I had the pleasure of being able to go and do some work with an amazing man called, Doctor Tim Holt. He works at Colorado State University, and he has been absolutely instrumental in reducing the prevalence of high altitude disease in these Angus cattle, and he's probably.
Measured heart pressures in about 2 million of these Angus cattle and looked at breeding genetics because we know it's associated that some bulls seem to produce animals that are very susceptible to high altitude disease, and some, that don't. We think it might be related to a haplotype of the angiotensin converting enzyme. But basically, these animals go into heart failure if they are susceptible.
And become sick and often die, when they are raised above, sort of 6 to 7000 ft. So, all the work that he's done has been about putting a catheter down into the pulmonary artery. So he puts a needle into the right jugular vein.
He feeds the catheter through and he measures the pressure within that pulmonary artery. And if that pulmonary Artery pressure is moderately to severely increased, then those animals that should be being raised extensively at maybe 9 or 10,000 ft above sea level, get moved down to feedlots at about 5000 ft in order that they're sort of finished in a different place. The other problem that you have when you've got susceptible and females breeding stock is that calves can get born with pretty pretty marked signs as well, and they get reversion to foetal circulation and they normally die pretty quickly.
And what we know is that horses, alpacas, yaks are pretty resistant to high altitude disease, and it's these European breeds of cattle, people, and turkeys that seem to be most sensible. And the challenge in these regions of the Rocky Mountains in North America, we've got Ethiopia, we've got the Ethiopian Highlands, we've got areas of the Andes, we've got areas of the Himalayas where there's a lot of land that's gonna be. Above 10,000 ft and maybe even higher, is, what else are you going to raise in these mountainous regions?
They have too much snow in the winter to raise, to raise sheep, and it's too cold to do anything really with arable crops. So cattle end up being their only choice. And in North America, because there's such a premium on Angus beef, and that's what people want to, want to raise.
So it's this real challenge. And this here is Tim. We've got the rancher holding these cows, and he can measure heart pressures in sort of 2 or 3 minutes per per animal.
So he puts a needle in, he feeds his wire in, it's connected to a, to a, a blood pressure monitoring machine, and then he can get a reading of what the pressure in that pulmonary artery is, and he does it all looking at pressure traces. So we went out there in 2009 to see what we could do with echocardiography. And the one thing I would say is the sort of 300, 350 kg, 6 to 9 month old steers and heifers were pretty feisty, for scanning in, for scanning.
Crushes. So, we, Tim measured all the pressures using his machine that went down into the heart, and then we got some, we got some ultrasound images. And in the time it took him to do 350 heart pressures, it took me about 40, I managed to get about 40, echoes.
So I've got some examples of mild, moderate and severe changes that we can see at high altitude. So this is an animal that's had got increased pulmonary artery pressures and. What we can see in this image is we've got some slight thickening of this right ventricular wall, which is one of the first changes we see when we start to get increased pressure within the pulmonary circulation.
Then this animal has got moderately increased pulmonary artery pressures. Sorry, I've got to switch my, laser pointer off to get my videos to play. And here, hopefully you can see, as well as having a thickened right ventricular wall, we've now also got this sort of increase in size of the, of the, of the diameter of the right ventricle.
And that's the next step that we get. We start to get right ventricular dilatation. And then this animal, so normal pulmonary artery pressures would maybe be around sort of 25, 20 to 25.
This animal had got pulmonary artery pressures of about 110. And hopefully, what you can see now is this right side of the heart is absolutely enormous. It's just dilated.
It's squashing the left side of the heart, and, and I mean The right function's gonna be pretty poor. Now, this animal was still like bouncing in the crush. So, heart failure, it might have been.
But all of these changes that you see, they'll reverse within 5 days if you can get these animals down from altitude. And that's exactly what these guys were set up to do. Tim goes in, finds the animals that have got, That have got high pulmonary artery pressures.
They load them up in a truck, they take them, take them down 3 4000 ft, and then raise them in the feedlots. And it's a real shame, right? Because, you know, these, these cattle can live extensively on some beautiful grasslands, but obviously they're gonna die of heart failure if they're not able to cope with the, cope with the altitude.
And then what Tim's done and that over time is he's, he's mapped, you know, the, the sires that produce resistant and susceptible, susceptible offspring, and it's certainly prevalence has become lower because of changes in genetics. So, we're now just gonna finish thinking about some rhythm abnormalities, and I think sometimes we maybe overlook these, in animals and, and part of that problem is, you know, often when we're presented with sick cows, they're tachycardic anyway, which can be pain, stress, and can be because they're hypovolemic. And therefore, sometimes those rhythm abnormalities aren't perhaps quite as clear as they would be if they had a normal rate.
So hopefully you can hear this. So a normal cow has got a, has got a, you'll often hear three heart sounds, S1, S2, and S3. And why we hear S3, which is associated with passive ventricular filling so commonly in cattle, I'm not sure.
And then sinus dysrhythmia is a pretty Common, normal rhythm abnormality that we pick up. It will often become more pronounced if we've also got underlying respiratory disease, but certainly is a very, very common finding. And when you do find animals that have got normal to lowish heart rates, and that sinus dysrhythmia or sinus arrhythmia can be very, very profound.
And this ECG that I'm showing you in this picture is recorded with a device that connects to a mobile phone, that costs about 80 pounds and you can literally just push it on the animal's side over the heart apex, and it will give you an. That you can record and save on your phone, and this is where this ECG has, has been taken. You often have to really wet the cow's coat, especially if it's a, a bit thick in order to get, in order to get good contact.
So this is an ECG taken from a 4 year old Holstein Friesian cow, and she just wasn't doing very well after an LDA surgery and she certainly didn't have a, a ping and no one could really identify what else there was. But what did become evident was that she was tachycardic and she had an irregularly irregular rhythm. And I'm sorry this isn't the most beautiful ECG that I've ever recorded, but hopefully you can see she's got sort of normal QRS's here, but she's got, there's a very, very irregular R to R interval and because her heart rates.
Sort of 100, it's not that easy to see. She doesn't have pee waves and she's got these sort of fibrillation waves sitting between the QRS complexes. So this cow had actually got atrial fibrillation, and it is, Well reported, we'll often see it secondary to a displaced Amazin, particularly right displaced Amazin, where we're more likely to have electrolyte derangements.
But atrial fib in, in cattle is associated with them really not feeling great. They'll often have quite marked. In milk production, they'll be pretty exercise intolerant.
They'll hang back from the herd, all because it's a, you know, it's a tachy dysrhythmia, and the heart's just not able to pump very well. Now, some of these animals will go back into sinus rhythm when you correct their electrolyte changes, and they're worth giving a bit of time. But if you can, and you can make it so they don't have to walk so far, you know, maybe kept close to the, to the parlour, life will be much easier.
And some of them never do go back into, into sinus rhythm. Now in the UK we don't have any drugs that we can use in food producing animals, and in other parts of the world, they certainly do use drugs that are used in. That are used in in horses, and Quinnadine being the, the common one that would be used.
And they do respond pretty appropriately to Quinnadine, if you ever, ever want to. I mean, in, in horses, we do DC cardio versions now where we put Wires down into the heart. If you did have a particularly valuable individual animal, this is certainly something we could do in cattle.
To my knowledge, I don't know anyone around the world that has done them, but, and there would be no reason why it wouldn't be a possibility. And then this was a, we had two young calves that presented to to us. They were going to be heifer replacements, and they, it had been identified on farm that these animals had both got, had both got.
The abnormalities. And what the farmer really wanted to know was they were between sort of 6 and 8 weeks old. What the farmer wanted to know was, was it worth continuing with them, or, or was he better to sort of cut his losses and ensure that he didn't keep them as heifer replacements?
So this is the ECG that we took from this very nice, this nice creature here. Here you can see some of our students getting some, pictures of his heart, and the, the calf's heart was, her heart. The calf's heart was absolutely fine.
We didn't find any abnormalities. She had no murmurs. But on this ECG what it showed was that she was having lots and lots of super ventricular.
Premature depolarization. So you can see that we've got these sort of normal beats coming here, but they're just coming early. So there's quite a lot of them, one there and one there.
And, you know, if you listen to this, it sounds a little bit like sinus dysrhythmia, but it, it wasn't. You can see they're sort of come in couplets, and then the R to R intervals are pretty steady in between. Now the risks of these super ventricular premature beats is they can turn into atrial fibrillation.
But certainly this wasn't a rhythm abnormality. We were terribly worried about. It wasn't impacting on, cardiac function.
And so what we said to the farmer was, definitely worth carrying on with this, with this animal, and that if we needed to, we'd check it. If he was worried, we could check it again in 6 months to see if they'd gone. And in 6 months' time, this animal had a sinus dysrhythmia, had a pretty normal, normal rhythm.
And this was a slightly older, sorry, this was a slightly older, Holstein Friesian replacement heifer. And again, people had, they'd been done a physical exam and felt that they could just hear some abnormal beats. And what you can see is that indeed, she was having some abnormal beats.
So we've got, this is sort of the normal. PQRST here. And then what we've got here is a, is a, a, a premature beat that doesn't look like it has a P wave in front of it and is a bit of a funky shape.
And then we've got another one here, and again, completely different shape to the, to the other complexes. So this was an animal that was having different forms, multifocal, ventricular. Premature depolarizations and, you know, the wreck that we checked her electrolytes, electrolytes all seemed to be normal.
No other significant abnormalities that we found. But you can see they are frequent. This is another section of ECG I've just got to show you, and they are frequent, but again, not frequent enough.
We need to treat them and they're not going to impact on. Cardiac function. So, again, same advice was given here, really.
Probably, you know, who knows? Was this, was this some inflammation of the myocardium? Had this animal, was it post-viral or post other infection that, you know, had sort of passed on?
But again, the, the advice was, why don't we see what happens in, you know, 3 or 3 months or so, see whether these go away or get more frequent. And again, they went away. So that's the end of my talk.
Thank you so much for your, your attention, and if any of you have any questions or there's anything I can help you with on this topic, please feel free either to email the webinar vet and they'll pass them on to me or to email me at the at the address below. Thanks very much indeed, bye bye.