Willow is a delightful Cocker Spaniel puppy, full of the breeds usual mischief. When I first met Willow she happened to have a rather round belly. As you may know when puppies get worms the belly can become rather enlarged. We decided with Willows owner to rule out worms first with a course of treatment. Although I had a suspicion something more might be brewing we decided to wait and see as there were no other problems found on a health examination. Months later when Willow was re-examined her owner was worried that although she was full of energy and playful, she was smaller than her siblings.On a closer examination we found that there was a hard lump we could feel in the front of her belly which we did not feel before so we booked her in for some blood tests, x-rays and an ultrasound scan. The blood tests were fine but the xray and scan showed an enlarged liver and a dilated blood vessel entering the heart.
Willows heart sounded completely normal and she showed no signs of weakness we would normally expect with heart disease. We suspected there was a blockage of blood flow back into the heart but struggled to see anything on a heart scan. We suspected a condition called Cor Tritriatum Dexter and referred her for a scan with a registered specialist. The cardiologist found a valve that had not formed properly between the chambers of her right heart but could not confirm a Cor Tritriatum Dexter. He recommended a 3rd opinion at the Royal Veterinary College in London.
The RVC confirmed Willows heart condition as Cor Tritriatum Dexter, a rare condition that had a 50% chance of resolving with heart surgery. The surgeons at the RVC had seen a handful of cases like this in their specialist cardiology department.
So what is Cor Tritriatum Dexter? Just to recap on how the heart functions you may remember that the heart has 4 chambers. This you tube video shows how the heart pumps blood. It uses a human heart but the principle is the same in all mammals.
Willow's heart did not form properly, leaving a membrane like a thin piece of skin dividing the right atrium (chamber) of the heart into two sections. The blue blood coming from the head and chest could enter the heart but the blood coming from the stomach and abdomen could not.
You would think this would create a serious problem but Willow seemed oblivious to it. It's amazing how the body compensates for problems. What made us suspect this condition was the fact that the blood from the back of the body was being trapped in the caudal vena cava making it much wider on xrays than we would normally see.
The green arrow below shows Willows Caudal Vena Cava which should be half the diameter it is. The red area shows where the blockage was stopping the blood from coming back into her heart from her abdomen. The blue arrows on the left show how the blood still gets into her heart from her head and chest.
So what happens to all the blood in her abdomen?
Well the blood takes the long way round and comes back via her spine. There a some small veins that travel along the spine from the back to the front of the body and these veins took over Willows caudal vena cava function and tried their best to get the blood back to the heart.
The picture below shows how the blood moves up to the spine as goes to the front of the body to get into the heart. There are also a few vessels that try bring the blood back along the bottom of the heart but I have not shown these below.
It turns out they were doing a good job because she showed no signs of illness. Her liver did enlarge as the blood pooled in it and she even developed some water in her abdomen. However she still ran a mile with no effort and kept her owners on their toes.
The surgeons at the Royal Veterinary College inserted a catheter into Willows vein in her back leg and moved it all the way to the back of her heart. They injected a dye into her blood via the curled up catheter that made the blood stand out black on xray. The green arrow shows the dilated caudal vena cava and you can see where the black blood stops at the red marker, The grey areas show the diluted dye getting to the heart via alternative routes which involve getting blood to the front of the heart because the main back route is blocked.
The surgeons passed a catheter into her caudal vena cava and then into heart, made a hole in the membrane (red line) and then inflated a balloon and stretched the small hole they had made to make it bigger.
This then allowed blood to flow from the caudal vena cava into her heart as it was supposed to. The image below shows the black dye in the blood now moving from the main vessel into the heart with very little blood trying to find an alternative route.
A few months on and Willows follow-up assessment shows she has excellent function and her blood is once again flowing as normal. She's a lucky Spaniel! Most heart conditions are very difficult to fix but fortunately we could do something in her case.
Willows heart sounded completely normal and she showed no signs of weakness we would normally expect with heart disease. We suspected there was a blockage of blood flow back into the heart but struggled to see anything on a heart scan. We suspected a condition called Cor Tritriatum Dexter and referred her for a scan with a registered specialist. The cardiologist found a valve that had not formed properly between the chambers of her right heart but could not confirm a Cor Tritriatum Dexter. He recommended a 3rd opinion at the Royal Veterinary College in London.
The RVC confirmed Willows heart condition as Cor Tritriatum Dexter, a rare condition that had a 50% chance of resolving with heart surgery. The surgeons at the RVC had seen a handful of cases like this in their specialist cardiology department.
So what is Cor Tritriatum Dexter? Just to recap on how the heart functions you may remember that the heart has 4 chambers. This you tube video shows how the heart pumps blood. It uses a human heart but the principle is the same in all mammals.
Willow's heart did not form properly, leaving a membrane like a thin piece of skin dividing the right atrium (chamber) of the heart into two sections. The blue blood coming from the head and chest could enter the heart but the blood coming from the stomach and abdomen could not.
You would think this would create a serious problem but Willow seemed oblivious to it. It's amazing how the body compensates for problems. What made us suspect this condition was the fact that the blood from the back of the body was being trapped in the caudal vena cava making it much wider on xrays than we would normally see. The green arrow below shows Willows Caudal Vena Cava which should be half the diameter it is. The red area shows where the blockage was stopping the blood from coming back into her heart from her abdomen. The blue arrows on the left show how the blood still gets into her heart from her head and chest.
So what happens to all the blood in her abdomen?Well the blood takes the long way round and comes back via her spine. There a some small veins that travel along the spine from the back to the front of the body and these veins took over Willows caudal vena cava function and tried their best to get the blood back to the heart.
The picture below shows how the blood moves up to the spine as goes to the front of the body to get into the heart. There are also a few vessels that try bring the blood back along the bottom of the heart but I have not shown these below.
It turns out they were doing a good job because she showed no signs of illness. Her liver did enlarge as the blood pooled in it and she even developed some water in her abdomen. However she still ran a mile with no effort and kept her owners on their toes.The surgeons at the Royal Veterinary College inserted a catheter into Willows vein in her back leg and moved it all the way to the back of her heart. They injected a dye into her blood via the curled up catheter that made the blood stand out black on xray. The green arrow shows the dilated caudal vena cava and you can see where the black blood stops at the red marker, The grey areas show the diluted dye getting to the heart via alternative routes which involve getting blood to the front of the heart because the main back route is blocked.
The surgeons passed a catheter into her caudal vena cava and then into heart, made a hole in the membrane (red line) and then inflated a balloon and stretched the small hole they had made to make it bigger.
This then allowed blood to flow from the caudal vena cava into her heart as it was supposed to. The image below shows the black dye in the blood now moving from the main vessel into the heart with very little blood trying to find an alternative route.
A few months on and Willows follow-up assessment shows she has excellent function and her blood is once again flowing as normal. She's a lucky Spaniel! Most heart conditions are very difficult to fix but fortunately we could do something in her case.
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