 Hi there and welcome. My name is Dr. Ashley Whitehead and I'm a senior instructor here at the University of Calgary Faculty of Veterinary Medicine. I'm a large animal internal medicine specialist and the associate dean of clinical programs. I do my clinical work at Moore Equine Veterinary Hospital and mostly work on horses. Today we're going to be looking at how your veterinarian is going to be assessing your horse if it has any cardiac issues. Now that could be from listening to your horse's heart with the stethoscope, doing an ECG which looks at the electrical rhythm within your horse is heart or even ultrasound in your horse's heart to look right inside of the heart. And so we're going to be starting out with a little bit of an anatomy background because you don't have any idea of what's going on inside of the heart if you don't know how it works first. And so these specimens right here are going to give us that background that's really needed so that we can get you on the ground floor inside of your horse's heart. What we have here are all specimens from animals and they've been gone through a process which is called plastination. And plastination is a process which takes the wet tissues and turns them into plastics and it does take a very long time to do this process but what it does mean is that these specimens last a very long time and students for years to come can be utilizing the same specimen and learning from them so it reduces the amount of animals that we need to teach our students which is a fantastic thing for us. Now this one right here is a heart it's actually a large dog heart but I wanted to bring this one even though we're talking about horses today because it gives you an idea of about the size of a human heart. So this is about the size of my heart here. Now when we are using these specimens we like to have them cut so that we can see all of the internal structures. Now each of my specimens that I have here are cut in different ways and when we go through the ultrasound I'm going to be using these specimens so that you can see the different cuts and understand the different angles and I'm holding the probe and you'll be able to interpret those images. Now these other ones are all horse hearts so this is more of a pony sized heart so you can see we've got a much bigger size than our dog our dog size here and then we have full size horse hearts here. Now when we're talking about horses hearts they're just the same as your heart or a dog heart we have four chambers in them so we have two upper chambers and two lower chambers and we call these left and right just similar to us even though in the horse it's going to be a little bit more angled down like this versus us because we're standing upright. Now the bottom two chambers are called the ventricles and the top two chambers are called the atria and so when we go through it starts on the right side in the top chamber so the right atria goes to the right ventricle then it gets pumped out into the lungs it goes through the lungs and gets that rich oxygen in it and comes back into the left side into the atria and down into the left ventricle and then it gets pumped out that aorta to the rest of the body to bring that oxygen rich fluid blood to the entire body. Now that's the very quick physiologic but it's really important because the left side of the body is pushing it to the whole body and so what that means is that that left side has a much bigger bigger job to push it everywhere and so when we look at it in this cross section where we've cut it right across the body you'll notice that it's very very thick on this side of it versus this right side of it is much thinner now you may say well that doesn't really matter much to me as the horse owner but when we go to do our ultrasound you will now be able to decide which side is the left side and which side is the right side just by knowing that the left side is much thicker because we're pumping to the rest of the body and the right side is much thinner and so we're going to use these specimens to show you our images on our ultrasound in just a second here you've already passed first year vet school and you didn't even know it in the last five minutes here we're going to show you a couple close ups of these so that you can get an idea inside of here as you can see we can see our two chambers so our ventricles and then up top here our atria and in between here are our valves now these valves here this one these are called our atrio ventricular valves and these are really important for preventing the blood from backing up as we have a contraction in the heart and we're going to be able to see these valves really easily on the ultrasound and I want you to pay special attention because of our horse Daryl here and you've seen him in the background Daryl is one of our teaching horses that we have here at the university and we have a wonderful herd of teaching horses that help us teach our students and Daryl actually has an issue with its heart and so I'm going to draw your attention to this part of the heart we're going to come back to this as we go along with our ultrasound of Daryl's heart so we've moved over to a Daryl here we've moved our stocks down just so that you have a little bit of a better view knowing that it's a little bit of a safety risk if this was done in general but we want you to be able to see things here for our video so first thing we're going to talk about here is listening to the heart so this is something that as a horse owner we do recommend as veterinarians that you do try this because it can be very helpful in an emergency situation for you to be able to take the horse's heart rate and it's valuable information to give the the veterinarian who may be a little bit further away is how to take a heart rate and to give us that number and it gives us an idea of how emergent the situation is so being able to take the heart rate beforehand practice is key in knowing what normal is for your heart so something for your horse so practice beforehand so this one here is one of my fancy cardiac stethoscope so you can see that it has a fancy way for me to hold on to it you can get much cheaper stethoscopes that you can use and learn how to use on your horse there are just human ones so you can get out of pharmacy even and I also have a second one here which has is a digital stethoscope and has this recording piece that actually sends the information over to my phone by bluetooth and so when i'm listening to the horse's heart I don't just listen over one spot so traditionally you know we kind of I always say you make a little ledge with the horse's elbow and we kind of push in here now he's got a very big tricep and a little bit of fat or maybe a lot he's a little over conditioned our friend here that's going to be a good spot to start with a lot of people want to be very low because we think of the heart being quite low in the chest but it's actually not now when we're listening over all three valves that are on this side now there's three on this side and one on the other we have to push forwards because the valves are actually this is our mitral valve then our aortic valve is up underneath of that muscle and then our pulmonary valve so you can imagine when we're listening to those three valves we have to get under the muscle and actually get right in there and you can see my hands are pushing under but we have to listen over those valves in order to hear for the murmurs because depending on how well those murmurs are if we just listen over one we may miss them so really important when we're doing cardiac exams is to listen over all of the areas being a really quiet environment which can be difficult in a barn which you know if some machines are going in such as to be able to hear all the way along so what we've got here is one of the printouts from that recording stethoscope and so what's really neat about the recording stethoscope is that some of them actually give us the ECG along with the audio waveform with the audio recording and so that's great for teaching it's also great for us as clinicians because we can see the murmurs and that helps us localize them in time with the electrical current that's going through the heart and so this one here is from a normal horse and what we're going to be listening for is the love dub so just like all species we have a love dub for the valves closing in the heart and so we're going to listen really closely here for love dub and a heart in the horse is very slow to have love dubs and so this is as I said about 40 beats per minute versus us in a human which is you know 60 or 80 beats per minute but it's amazing in the horse when they start to exercise that's going to go up a hundred even 200 beats per minute and so it's going to go up really fast and this is a normal horse as I said so we're going to listen for love dub love dub love dub so let's listen to that one more time we're going to listen for those love dubs love dub love dub love dub sometimes it's easiest to tap your foot with it even love dub love dub love dub okay so now that you've heard the love dubs of a normal horse now we're going to listen to our patient Daryl and you're not going to hear any of those love dubs now this is where his murmur is loudest and he actually has a couple different murmurs associated with his heart condition and I picked the loudest one for you and I want you to see if you can hear the murmur which I think you should be able to hear swoosh swoosh swoosh swoosh swoosh well play it one more time and you may say well there's no love dubs well there probably is some love dubs if we listen at different parts of his heart but what we're hearing right now is the turbulence of the blood flow and when we get to looking at his um ultrasound of his heart this is where the turbulence is strongest of the blood swirling around and that's really what murmurs are isn't it their turbulent flow of the blood when we hear the normal love dub that's where the valves are closing all right let's listen to this again almost like a washing machine all that turbulent blood flow other parts of our cardiac exam is at the beginning I said we assess the vessels as well and so we're just going to have them back up a little bit so you can see a bit better is assessing the jugular vein and so when we talked about the right side of the heart the blood is emptying from the whole body into there well one of those areas is the jugular vein and so we're going to assess on that jugular vein by holding off the vein seeing how it fills and then we're going to see how it empties below the other thing is here right underneath the jaw here if you kind of run your finger along under the mandible or the jaw there's something that's about the size of an earthworm and that's a large artery so similar to we have under our jaw and if you just lightly put your fingers onto that earthworm you'll be able to feel it pulse now a horse's heart rate is usually quite low usually around 40 beats per minute or less and so you have to sit there for quite a while to be able to feel it pulse pulse pulse pulse pulse and so you can feel that pulse and that's another place where you can get your horses heart rate now for us when we have a horse that has a heart cardiac condition we can learn a lot from their pulses in addition to listening and looking at their other vessels and so we're going to assess all of those things along with this is one of those ones it's kind of a clue to the cardiovascular system is also the respiratory system so our cardiac evaluation is partly about auscultation partly about palpation and feeling and looking at our valve our vessels and partly about assessing how our horse's respiratory tract is also doing how are they breathing and so we may have the horse go out and do some exercise the next piece of it is how is the electrical piece of their heart doing and that has to do with our ecg now our ecg we can attach a whole bunch of leads to them what you're going to see in a second but some of the newest stuff comes with little tiny ecgs that we can attach with our phone and we actually hold our phone to the horse's heart just like this and it provides us with an ecg lead and so it's it's a little bit different than our fancy leads but this can give us a bit of an information just on the fly while we're at the farm and what i've actually had is horses that have some abnormalities that we want to track we can have our horse owners do this and send us the information by email and that way we can follow our horses you can see that i then have my ecg from this horse and i can then assess that little bit of an ecg right off of my iphone so what we're doing now is we're doing what's called an echocardiogram which if we were to break that word down in latin is gram is basically doing some kind of testing procedure echo is just what we think of when we think of like echolocation it's using sound waves and cardio is heart so we're doing a test for using sound waves on the heart and that is using our ultrasound here this is our cardiac probe and it has a little square end on it which sends out sound waves in a very specific way it essentially gets a triangle view so it has a very triangle end or pie shape view on it which allows us to go quite deep in the in the chest to look at the horse so we use gel just like in humans as well as some alcohol and the reason that we use alcohol is that we have hair now we've clipped an area on daryl here to help us get rid of some of that hair now when we are doing this ultrasound on him we are going to be looking at different views and the different views are obtained by moving this probe around in different views so the one that i was just giving is essentially looking at the heart in like this so this is the view that i was getting when i was looking at it so you may ask why are we um echoing on the right side of the chest when the heart is usually on the left side of the chest just like in most other mammals now the reason for that is we actually have a little bit of a window on this side because the lungs make a little bit of a window to allow the us to see through now the second view that we get with it is called a cross section and that's when i turn my probe a little bit further and we get this view like this and so it's basically a cross section of the heart so the other thing that you'll notice that we have hooked up on him is that ecg that i was talking about before so the ecg leads in this case we have three that are attached to him that comes up on my screen with simultaneously with my ultrasound and that allows me for when i'm doing measurements of the heart because i actually take measurements of the different chambers while i'm doing my ultrasound to be very exact to the timing of the different cycles of the contractions of the heart and so this ecg leads are attached on and they go in front of him behind the heart so that i know that the electrical conductance going through the heart and then this is what we call basically a ground similar to if you think of when you're wiring your house this is my ground wire or a ground ecg lead so it's just giving me a base somewhere else now when we do ecgs in the field we actually have one that we have that can do on your farm for if your horse has an issue and we need to do 24 hours or a halter monitor and so those ones we put on and we attach a little box to the main and it's only about this size and that way we can take the ecg reading for 24 hours to make sure that nothing is going on that would be wrong that may not be just when we sample the horse while we're watching it we also have ones that we can do while your horse is exercising in case something only happens during times when your horse has um arrhythmia when maybe it's at full exercise while you're out on the cross country course or while you're racing or while you're doing a barrel race and so same thing we put on these leads that go around and then the little box attaches to either the horse's main or the saddle or even the harness and we can do those at exercise and get an idea and those are called the televette so we're starting here on the left side of the heart with our longitudinal section or long section of the heart and so I put the image up at the top here so that you're oriented to our heart at the very top of the screen we're closest to the skin then our body wall and then of course we're on the right side so the right ventricle is closest at the top there on the right side of the screen from where you're viewing is the right atrium and then the right ventricle is at the top there and then that thick band of tissue is the intraventricular septum and the intra means between so it's the band of tissue between the ventricles then we have the black area which is the cavern of the left ventricle and then down at the bottom of the screen you'll see coming in and out because we don't have as good of a contact and that's pretty deep down that's almost 30 centimeters away from the top of the screen is the ventricle wall on the other side of the heart and then on the bottom right hand side of the screen is the right atrium now we don't always get the best contact because we are very deep into the heart so this is when I was talking about that cross section of the heart so this is that same ventricle but we've turned the probe and so now we're cutting the heart in in half a separate direction and so we've got a mushroom of the heart we're right on the valve that's opening and closing and I call this my fish mouth valve because it kind of looks like a fish mouth opening and closing so I've done a still image here and I'm going to orientate you to where we're at so of course we're still on the right side of Darryl so the very top of the screen is on the right side so we've got the skin and his body wall and then of course everything is black is essentially his blood and anything that's white is tissue that's reflecting back the signals to the ultrasound now that bright white area that's that's going along there is the intraventricular septum so the area between the two ventricles now you can see that I'm measuring something so there's a little caliper which has two little arrows on them and we'll come back to what that is then we've got a large black area and that's the left ventricle about midway down the screen and then below that at the very bottom of the screen is a bit of a white area just above the ECG and that's the far side of his heart now on the middle where we have that bright white ventricle intraventricular septum normally that would go all the way from the left of the screen to the right of the screen and be a big band of white and you're noticing that there is a black area where those caliperus are there is a bit of a hole there and this is actually what is wrong with Daryl there shouldn't be a hole there and you'll see that on just below that there are some kind of wispy strands that are lifting up and that's part of his valve or atrial ventricular valve and then just above the the little hole that he has there's more wispy strands and that's his second atrial ventricular valve we have this hole in his heart which can cause some significant issues for him now if you see the measurement of it at the top of the screen that's actually two centimeters some horses have very small holes which is only about a millimeter or two millimeters and that doesn't cause many issues and those horses can actually be race horses and not have many issues now these are developed because of a defect while the horses being developed in utero that muscle that's being created in the intraventricular septum is sliding and coming together and in him it did not come together appropriately and so what we end up having is this embryologic defect and that's what causes the issue in our next view we're going to see how the blood flows through that area so here you can see that flow going right across straight through from the left side to the right side and the reason that it's flowing right across from the left side to the right side is the left side has really high pressure because it's pushing really hard and then the low right side is lower pressure because it's going into the heart so it doesn't have a lot of pressure in it and so it's going straight across there and you can see it flowing and all that turbulence is creating the murmurs that Darrell has it's just flowing across there like crazy with that big flame going all the way across there so I wanted to show you where that position was where Darrell has that hole in his heart in that intraventricular septum so you saw that it was really close to these valves here and so it was right below the valve in this area of the intraventricular septum and it was about two centimeters in length there now as I mentioned they can be very small like just a couple millimeters and the horses can do okay but larger ones can cause significant issues with exercise and performance and even larger ones can be fatal in them and so that's in that intraventricular septum right below the valve and that's probably the best spot that they can have them in if they're lower down then they cause even more issues in the horses and those are called a VST or ventricular septal defect now horses can also have them up top in the atrial septum and those are called ASDs or atrial septal defects so Darrell and I would like to thank you for joining us today and learning a bit about the cardiac assessment in horses now there are cardiologists that do this and that's their only thing that they do and then there are those of us that are internal medicine specialists that have an interest in cardiology and many veterinarians will do the initial cardiac assessment in your horse as well and so we are a team that work together to get your horse in peak performance and we work together to make sure that things are going great so we look forward to working with you and for answering your questions in our question and answer I'd also like to thank everyone who's donated to our equine health fund and main donations to the University of Calgary our ultrasound machine here that we have was donated in part through our equine health fund and as I mentioned so were our digital stethoscopes we rely on donations for our equine health fund for not only our clinical equipment and teaching equipment but for also our clinical research that we do out in the field not only for our clinics clinical partners learning more about our clinical cases but also advancing our clinical research to learn more about diseases that are out there and what we can do to increase our our horse health throughout Alberta and beyond so get your questions ready and we'll be talking with you soon