Whitney Veterinary Hospital Heart Disease

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Heart Disease: The Beat Goes On! Nancy J. Hayes, DVM Whitney Veterinary Hospital and Whitney Cat Care Clinic What's Normal?
	One: The normal heart is made of of four chambers: The atria which gather the blood and pump it into the ventricles, and The ventricles which pump the blood out to the body. The left side of the heart pumps blood to the body, while the right side of the heart pumps blood to the lungs. Valves are the little flappers that separate the two chambers.

Would you like to listen to some normal heartbeat sounds? - Normal 1 Normal 2
What is Circulation?
Circulation is essentially the heart's function. It pumps blood out to the body and returns it to the heart. Then the heart pumps the blood back out to the lungs and back to the heart. Blood pressure is the result of the pumping action and the blood return to the heart. Circulation is a one-way system: That means the blood pumps out from the heart and around and back to the heart and should not flow backwards through the vessels. The circulatory system also includes arteries, capillaries and veins.
So What Happens? (Simplified)
Oxygen (O2) is picked up by the blood in the lungs. It leaves the left side of the heart via arteries. The arteries branch into capillary beds. In the capillary beds, the O2 leaves the vessels and goes into the tissues as Carbon Dioxide (CO2) is picked up from the tissues and carried into the veins. The blood with carbon dioxide is returned to the heart (right side) where it is pumped to the lungs to trade the CO2 for O2 - and the process starts again.
More On Capillaries:
Capillaries by nature are leaky to allow the oxygen out and the carbon dioxide in Fluid and other products also move in and out of the capillaries, allowing the feeding of tissues. -Fluid, O2, and other nutrients are pushed out - (partially due to blood pressure) - CO2, waste products... are pulled/pushed back in
Oh No! The pump broke down!
The pump is broken when the system becomes leaky and the pressure becomes too high or too low. Because circulation is a one way system, if the leak allows pressure to build behind the leak, the chamber will swell, and the pump will break down. First the leaks: The valves don't close completely --Blood leaks backwards when the heart beats (pumps) --An example of a leak would be a valve that does not completely close. When this happens, blood can pump backwards through the valve and into the wrong chamber. This creates a sound called a murmur. Murmurs are graded based on their volume. The louder the murmur, the higher the grade. Unfortunately, the grade does not necessarily indicate the severity. Murmurs are graded on a scale from I-VI Grade I leaks are very soft Grade VI leaks are loud The severity of the murmur is not based on the volume

So What Happens?
First the leak occurs When the leak occurs, some of the backflow stretches the chamber behind it For example: the mitral valve which separates the left atrium from the left ventricle is commonly found to leak. Each time the heart beats, some of the blood leaks backwards into the left atrium. At the same time, some blood is trying to get into the left atrium from the lungs. This causes the stretching of the chamber.

So What!
Because of the reverse flow, the atrium begins to stretch from volume overload (and the pressure goes up) The result is the left atrium enlarges and then it begins to leak backwards into the pulmonary vein! As the stretching continues, we get volume overload of the atrium and back pressure goes behind the atrium into the lungs.

Trouble in Paradise! Now that the left atrium is overloaded, the back pressure leaks to the lungs The lungs (as do all tissues) contain capillary beds. If the pressure is backing up through the veins, that will cause increased pressure in the capillaries. This increased pressure allows fluid to leak back out into the tissues (in this case: the lungs). If this happens in the lungs, the lungs will fill with fluid. This is what is called Congestive heart failure
Consequences: When the blood backs up, the pressure gradient gets out of whack and now fluid doesn't return to the vessels as it should. Some additional fluid may even be forced out of the capillaries When fluid leaks from the capillaries, it builds up in the tissues. The symptoms of the fluid are a result of which tissue it builds up in. If this happens in the lungs, fluid builds up in the lungs (alveoli) and causes coughing and an inability to absorb O2 (oxygen) Now the body is starved for O2, the heart pumps harder, and a vicious cycle is set up
So What Are the Symptoms?
Remember the original chart? The symptoms depend on where the leak is When the valve leaks, the blood backs up The fluid will build up behind the leak		Looking at the slides, one can see that if we follow the original chart, --realizing that blood pumps from the heart to the body, - back to the heart, - and into the lungs, - and then back to the heart: -- if a leak occurs anywhere in the system, the backup will begin at the leak.
In other words, if we have a leak in the left side of the heart, fluid will back up into the lungs. If we have a leak in the right side of the heart, the fluid will back up into the body.

If the Mitral valve leaks (left side), the fluid builds up back in the lungs. Coughing, shortness of breath, poor color (cyanosis) Loss of appetite, inability to exercise Eventually they cannot breathe		If the Tricuspid valve fails (right sided), the back up of flow is towards the body. The fluid will build up in the abdomen, and edema of the legs can occur Loss of appetite, inability to exercise, and a bloated abdomen are common
So - Let's talk specifics:
Mitral Valve Insuffiency (LA:LV) Common in small older dogs. Symptoms include: Increased blood pressure Coughing (moist) Respiratory difficulty Mitral valve insufficiency is common in small, older dogs. In fact, some suggest that 80% of small older dogs have a mitral valve insufficiency. Tricuspid Valve Insuffiency (RA-RV) (Right Atrium-Right Ventricle) Heritable diseases- (seen as dilative cardiomyopathy), Symptoms include: fluid in legs (edema), and abdomen loss of appetite Right sided heart disease can occur in many breeds as a heritable problem, as well as in smaller breeds. Symptoms of this kind of heart failure include distended abdomen and a loss of appetite.
Specifics continued:
Tricuspid valve Valve Insuffiency (RA-RV) Heritable diseases- (seen as dilative cardiomyopathy), Right sided heart disease can occur in many breeds as a heritable problem, as well as in smaller dogs and specific breeds. Symptoms include: fluid in legs (edema), and abdomen (bloating) loss of appetite *Hypertrophic cardiomyopathy* is primarily a disease of cats. This can be specifically seen in longhaired cats and many of the purebreds, such as Persian.This disease can be devastating. In this disease, in addition to having a leaky valve, the heart itself becomes thickened. The thickening of the heart leaves no room for the blood and consequently the heart rate becomes very fast. Symptoms of this disease can include sudden death, breathing difficulty and high blood pressure, as well as blindness.
More Specifics: Dilative Cardiomyopathy Cockers, dobermans, and taurine deficient cats Heart becomes dilated, floppy and doesn't pump Weakness, fluid build-up in abdomin and lungs, loss of appetite *Dilatative cardiomyopathy* is another inherited disease that is also seen in dogs, (especially cockers, dobermans, and others), as well as some cats that are taurine deficient. Taurine is an amino acid that is found in most commercial diets. In this case, the heart becomes large and floppy, and the walls become thin. The heart becomes a large balloon that barely pumps. Weakness and fluid buildup are very commonsigns.
Arrhythmias: Can occur in any breed Are usually secondary to other heart diseases Some arrhythmias are fatal, others are treated medically or with pacemakers Too many to list An arrhythmia is an irregular heart rate. There are many reasons for arrhythmias and therefore it is beyond the scope of this particular discussion. However, arrhythmias are taken into consideration during evaluation of the heart.
Who's at risk? Certain breeds such as: Poodles, maltese, yorkies Cavilier King Charles Spaniels Cockers, dobermans Some giant breeds - such as Great Danes Obese pets Older pets There are many breeds at risk for heart disease. However, other factors include *obesity,* - which is becoming more common in our pets - as well as *aging changes.* Because we cannot change age, nor can we change the breed, it's important to pay close attention to their weight.
Can We Prevent it? Help them stay fit and healthy Don't let them get fat! Annual exams, especially if they are at risk Bi-annual exams if a problem has been found While heart disease cannot be 100% prevented, risk factors can be reduced greatly, similar to the way they can be in people. Keeping them fit and healthy and not allowing them to get fat are very important. Additionally, annual examinations will help to detect diseases in early stages, when they can be treated more easily.
How is the diagnosis made? Physical exam Blood Pressure checks Radiographs (X-Rays) Echo (ultrasound) ECG Diagnosis of heart disease is made on physical exam, along with other modalities. Most heart conditions are detected during the annual physical exam. Blood pressure checks, x-ray and ultrasound may also be used and even ECG's if an arrhythmia is detected.
The Physical Full examination Listen to the heart Murmurs Arrhythmias Check the pulses Check the color and refill time The physical examination (which is performed annually) will help detect heart disease in its early stages. As pets get older, semiannual heart exams may be indicated. During the physical exam, we listen carefully to the heart to detect murmurs and arrhythmias. Additionally, we check for pulse character and the color of the mucous membranes to determine how well the heart is pumping.
Blood Pressure Checked just like in people Primarily look at the systolic pressure Should be less than 140 mmHg, but in a frightened or stressed pet it could be as high as 170 Blood pressure is measured in pets when concern for pressure problems is detected. Just like people, the systolic pressure should be *below the 140 mmHG.* Also, just like in people, stress and anxiety can increase the blood pressure. Blood pressure measurements are taken very much like they are in people, with a unit that pumps up the pressure and listens for the return of blood to the leg.
Radiographs (X-rays) 2 views are taken The heart size and shape is evaluated The blood vessels are examined too Lungs are checked for evidence of fluid build-up Radiographs (otherwise known as x-rays) are also taken. These help us to determine the size of the heart and whether or not the vessels are OK. It also lets us look at the lung fields to make sure that the lungs are not filling with fluid. Echo (Ultrasound) Can see the heart while it beats Allows us to measure each chamber and find the leaks Allows us to follow the progress of the disease and the success of the treatment

ECG - Electrocardiograph Not used as much now that Echo is available Used to see arrythmias on paper (electrical activity of the heart) Used to detect electrical abnormalities - such as AV blocks The ECG is not used as commonly anymore. With the advent of echocardiography and excellent radiography, we are better able to evaluate the heart with these modalities than we are with ECGS. The ECG is primarily used to detect arrhythmias.
Can we treat Heart Disease? Yes! Although heart disease is a very serious illness, if the disease is caught early and if the condition is not too severe, many treatment options are available. We usually look at heart disease as a long-term treatment and not as a curable disease. Depends on the type of heart failure Common treatments may include: Decreasing the blood pressure Improving the pumping ability Decreasing the fluid in the organs that are affected Monitoring is vital How do we treat it?
Treatment depends on the type of heart disease and whether or not we're trying to control blood pressure or heart failure. Because each type of heart disease is different, we first have to determine what type of heart disease we are dealing with. Medications can then be prescribed accordingly. Once medication is started, monitoring is vital. This may mean some repeated checks of blood pressure, x-rays or even echo.
Will they be all right?
The prognosis depends on the disease and the severity Many conditions can be controlled for a long time, - but heart failure is a major cause of death in pets - especially in small dogs Catching it early is very important Get check ups regularly Once diagnosed: follow up monitoring is important to keep these patients balanced Unfortunately, some of these diseases are worse than others The prognosis is good if caught early. Although, many times heart disease will progress to a fatal condition in many pets. With early detection, the outlook is much improved. Proper administration of medications and follow-up monitoring help keep pets in balance so that they can live long and healthy lives. *This is Jazzy. She loves a good dip in the pool*
If you have any questions regarding heart disease and your pet, please feel free to call us at 309-685-4707 or at 309-685-4715. We at Whitney's would be happy to help you with your pet regarding this problem. For further information about this topic, we would suggest the following links: Americal Animal Hospital Association AAHA Healthy Pet American Veterinary Association - Care For Pets
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Heart Disease: The Beat Goes On!

Can we treat Heart Disease?

Yes!

Will they be all right?