Why does my pet need a Veterinary Cardiologist?

Your veterinarian has recommended you see a veterinary cardiologist to better define the nature and type of heart problem suspected in your pet. Just like cardiologists in human medicine, veterinary cardiologists have additional training in the form of internships and residencies 3-5 years beyond veterinary school.  Board-certified cardiologists are specialists in veterinary cardiology and have passed 2 successive years of examinations to become Diplomates of the American College of Veterinary Internal Medicine within the College of Cardiology.

When will the doctor explain the findings to me?

When does my doctor receive the cardiologist's report?

Communication between CVCA and your primary care veterinarian is critical to optimal care for both your pet and you.  CVCA will fax a full report your family veterinarian the same day your pet is seen and will also mail a hard copy of the records. Any bloodwork results or ECG tracings will also be sent to your veterinarian the same day of your appointment.

What tests will be performed during the visit with the Veterinary Cardiologist?

Initially, a complete physical examination will be performed, paying particular attention to your pet's heart and lung sounds.  Based on these initial findings and the history of your pet's previous findings, additional tests will likely be recommended.  The gold standard for diagnosing structural heart disease is the echocardiogram.  Although your primary care veterinarian may have an ultrasound machine, the cardiologist's echocardiogram is performed with state-of-the-art equipment and interpreted with their background of additional training specific to veterinary cardiology.  Color flow Doppler mapping and flow velocities are also performed and used to analyze your pet's heart.  If your pet is having a heart rhythm problem or is a potential candidate for anesthesia, an ECG and/or a 24-hour Holter Monitor may also be recommended.  The cardiologist will interpret the ECG immediately.  This will define the cardiac rhythm to determine if medications are required to assist in the maintenance of a normal heart rhythm.

Can I stay with my pet during the exam and echocardiogram?

Absolutely, yes.  We believe an accurate assessment of your pet can best be made with you present and calming your pet during the examination and tests.

Will my pet's fur be shaved?

No.  With the advanced technology used by CVCA there is rarely a need to shave fur, unless the pet is heavily matted.


Does my pet need to be sedated to perform the tests?

Almost never.  We feel the most accurate cardiac evaluation is achieved on an awake patient.  Over 99% of the pets we examine do not require sedation to complete their evaluation.  Patients with heart disease are at risk for adverse reactions when given sedatives.

What should I bring to a visit?

Your pet's medical records, blood results, X-rays or ECGs that may have been done recently.  This prevents unnecessary repetition of previously performed tests.

Are cardiac medications for my pet expensive?

 Many of the medications we prescribe are primarily used in human medicine.  As a result, some are under patent and can be more expensive if no generic is available.  Our staff is well aware of the cost of medications; however, and will help you try to keep costs down while still giving your pet optimal therapy.

What is the difference between a visit with a cardiologist versus a radiologist?

A visit with a cardiologist includes a complete examination of your pet, immediate discussion of the findings as will as continued treatment and management of your pet²s cardiac disease over time. You will remain with your pet during most of the diagnostics, including the echocardiogram.  A radiologist is trained in imaging modalities not in the treatment of disease states.

What are the most common cardiac diseases?

1. Dilated Cardiomyopathy
   Dilated Cardiomyopathy (DCM) is a disease of the heart muscle which causes the heart to enlarge and not function properly. The disease usually afflicts larger breeds of dogs, such as the Doberman Pinscher, Scottish Deerhound, Boxer, Newfoundland, Golden Retriever, Labrador Retriever, and the Irish Wolfhound. However, it can also affect both the English and American Cocker Spaniel, and rarely, other small breeds of dogs. The occurrence of Dilated Cardiomyopathy increases with age and typically has an age of onset between 4 to 10 years. The cause of DCM in dogs is still unknown; however, many factors suggest a genetic cause.

   Dilated Cardiomyopathy usually affects both the left and right sides of the heart, with either side being more severely affected. Typically both the ventricle (lower chamber) and the atria (upper chamber) enlarge, and the ventricle loses its ability to contract and pump blood out to the body or the lungs. The consequences of the heart failing in its ability to pump blood can be compared to a simple mechanical pump. If the sump pump in your basement fails, water backs up into the basement; if the left heart fails, fluid backs up into the lungs, and if the right heart fails, fluid backs up in the abdomen or the space surrounding the lungs.

   Long term prognosis for Dilated Cardiomyopathy varies considerably. Most dogs with signs of heart failure at the time of diagnosis die as a result of the disease within six months to two years. Unfortunately, some dogs, especially certain breeds subject to a more severe form of the disease, may survive only weeks to a couple of months.

   Treatment of Dilated Cardiomyopathy is aimed at both improving the heart's function and controlling the signs of congestive heart failure. Drugs such as Lanoxin (Digoxin, Digitalis) are used to help the heart contract better and to slow the heart rate down if certain arrhythmia (electrical disturbances in the heart) exist. Once your dog is started on Lanoxin, you will be asked to watch for signs of digoxin toxicity that, although uncommon, include loss of appetite, vomiting, diarrhea and lethargy. These adverse signs can hopefully be avoided by having a blood test run by your regular veterinarian 7-14 days after the drug is initiated. To check for appropriate levels of Lanoxin in the bloodstream, a blood test must be drawn 6-8 hours after your dog's morning dose of Lanoxin.

   Diuretics are also used to help both control and prevent accumulation of fluid in or around the lungs. Lasix (Furosemide) is usually the drug of choice. Potential side effects of diuretic use include increased thirst and potentially increased urination. Another essential drug that is used in the treatment of Dilated Cardiomyopathy is termed a balanced vasodilator. This helps the heart pump more effectively against the pressures of the arteries and veins. Examples of this drug include Vasotec, Enacard, Zestril, Prinavil and Lotensin. These drugs are usually started gradually, with a low dose, and then build up to your dog's required dosage. These drugs can occasionally interact with the kidneys. For this reason, you will be asked to see your regular veterinarian in 7-10 days, 4 weeks, and then every 3 months to have a chemistry blood panel checked to assure that kidney function is preserved.

   Other drugs utilized in the treatment of Dilated Cardiomyopathy are aimed at controlling cardiac arrhythmia. Arrhythmia can be very problematic in some cases of DCM and can even be life-threatening. Certain breeds are more predisposed to this additional problem. If possible, it is a good idea to buy an inexpensive stethoscope to monitor your dog's heart rate and rhythm. Keep a journal of these records and if you are seeing a progressive increase or decrease in your dog's heart rate, or hear an irregular heartbeat, please call our office.

   It is also important for you to monitor your dog's overall attitude and outwards signs. If you notice any heavy/labored breathing, coughing, fainting spells, restlessness, or profound lethargy, please call us or see your regular veterinarian as soon as possible.

   Finally, your observations at home and your dedication in administering the prescribed medications in conjunction with our advice is what will help your dog the most. You know your pet the best. If you feel there is something wrong or you have any questions, please don't hesitate to call our office.

2. Cardiomyopathy in Cats
   The most common cardiomyopathy (heart muscle disease) in cats is Hypertrophic Cardiomyopathy. This form has many variations, and is defined by thickening of the primary heart muscle, the left ventricle. Depending on the specific variation, the problem can be an abnormality in the blood flowing into or out of the cat's heart. In conjunction with echocardiographic and other examination findings, this differentiation helps determine which medications your cat requires. With appropriate medication and early intervention, we can frequently achieve stabilization of the disease, and sometimes reversal of the problems.

   A genetic predisposition to the development of hypertrophic cardiomyopathy has been found in Maine Coon and American Shorthair cats, with a suspected genetic predisposition in Ragdolls and Persians. Cats in the 1-4 years age group have a tendency toward a more aggressive type of the disease. Male cats are also over-represented.

   A common secondary change in cats with cardiomyopathy is enlargement of the left atrium. This finding is particularly worrisome in cats because they are susceptible to blood clot formation. If your cat has an enlarged left atrium we may prescribe aspirin therapy (children's aspirin twice weekly is safe in cats or other medication to try to delay or prevent blood clot formation. Unfortunately, the development of a blood clot is unpredictable and can occur on any medication. Blood clot formation can result in a cat being paralyzed in the rear legs, limping on a front leg, exhibiting episodes of abnormal behavior or even sudden death.

   Older cats may have a thickened heart muscle, due to an underlying systemic cause. In our middle-aged and older cats, high blood pressure, kidney disease, and hyperthyroidism are common problems that increase the workload of the heart muscle and cause secondary thickening. We always try to rule out a potential underlying cause before we make the diagnosis of hypertrophic cardiomyopathy. If your cat has another problem, the response to therapy for that primary problem usually improves and may resolve the secondary heart changes. The response to any therapy depends on the stage of the disease, with the best response occurring earlier in the course of the problem.

   Restrictive Cardiomyopathy is another type of heart muscle disease. This form can be a late state of hypertrophic disease, or may be a primary entity. Unfortunately, restrictive cardiomyopathy presents a much greater challenge in it treatment. These cats tend to have very large left atria and are usually at high risk for the development of a blood clot and heart failure.

   Both types of cardiomyopathy can cause congestive heart failure (fluid in the lungs). Sometimes there will also be fluid around the lungs in cats with heart failure (pleural effusion) and that problem is best treated with physical removal of the fluid. If your cat has experienced an increased effort or rate of respiration he/she may have experienced an episode of heart failure. Multiple medications are typically recommended to improve this situation and try to maintain your cat's normal lifestyle and appetite. If your cat has not been eating for several days, we may also recommend placement of a feeding tube to provide the calories and fluids your cat needs to recover.

   Unfortunately, feline patients hide signs of disease instinctively, and many times develop advanced forms of cardiomyopathy because they have hidden their problems so well. As with all heart disease, early diagnosis is the key to achieving the best possible clinical response.

3. Valvular Disease
   The most common form of heart disease in dogs is valvular disease. This disease typically affects older, smaller breeds of dogs. The primary valve affected is the mitral valve, which is located on the middle of the left side of the heart. The edges of the valve become frayed and allow backward flow of blood within the heart. A normal heart valve keeps blood flowing in the forward direction only with no backward flow. With time, backward flow of blood overworks the heart and causes enlargement of both the primary muscle pump (the left ventricle)and the chamber that receives this backward flow (the left atrium). As the left ventricle enlarges, the strength of the pumping action deteriorates and medication to help this problem is required. With enlargement of the left atrium, the dog becomes at risk for the accumulation of fluid in the lungs (congestive heart failure.)

   Congestive heart failure causes an increase I both the effort and rate of breathing. Most dogs also cough many times throughout the day, particularly after lying down, when they have fluid in their lungs from heart disease. If this is the case, several medications will likely be prescribed to decrease the workload of the heart and maintain your dog's good quality of life.

   Some medications can cause side effects which can cause a deterioration in your dog's appetite or attitude. Please call us if there are any negative changes in your dog after initiating therapy. We can then make the appropriate adjustments in your dog's medication. Some dogs may always have a slight cough but they should feel good and hopefully better than before, with medical therapy.

   The tricuspid valve is the valve on the right side of the heart and also is commonly affected with degenerative disease causing backward blood flow or leakage. If the pressures in your dogs lungs are elevated (pulmonary hypertension) we can analyze the speed of the tricuspid leakage to estimate the pressures in your dogs lungs. This analysis using Doppler technology helps us evaluate the severity of your dog's heart disease and can be helpful in determining if any lung disease is also present.

   With appropraite therapy and close monitoring, dogs with valvular disease can have a good quality of life with minimal to no discomfort or coughing. Valvular disease is progressive problem therefore most dogs will need multiple medications as time goes by and th edisease progresses

4. Cardiac Murmur
   A cardiac murmur is a prolonged audible vibration heard during a normally silent period of the cardiac cycle.  A murmur frequently indicates heart disease.  However, some heart murmurs are innocent or functional.  Murmurs are often associated with high-velocity blood flow or with fluid vibrations that are created as a result of disturbed or turbulent blood flow.  Murmurs can also be created due to a decrease in blood viscosity (anemia) and/or increased adrenaline response (physiologic/functional).  The gold standard test used to determine the cause of a murmur is an echocardiographic study.  This study allows visualization of the turbulent flow and identification of its cause.

5. Systemic Hypertension (high blood pressure)
   Systemic hypertension is a sustained elevation in arterial blood pressure. Typically, systolic blood pressure greater than 160-180 mmHg is considered abnormal (this may be an underestimation for the extremely stressed feline patient).  Hypertension that develops in the absence of underlying disease is known as primary hypertension.  Primary hypertension is very common in humans but this is not the case for small animals. In cats, systemic hypertension is most commonly secondary to renal disease and/or hyperthyroidism.  In dogs, systemic hypertension is most commonly secondary to renal disease, Cushing's disease (hyperadrenocorticism), diabetes mellitus, and/or pheochromocytoma (a tumor of the adrenal gland).
   
   If hypertension is diagnosed one needs to rule-out the above-mentioned underlying causes along with extreme stress (the white coat effect) prior to starting antihypertensive therapy.  There is a common notion that cardiac disease causes high blood pressure, but this is not true in pets.  High blood pressure can create secondary heart problems, such as left ventricular enlargement and aortic valve abnormalities.

6. Subaortic Stenosis
   Subaortic stenosis refers to a narrowing of the left ventricular outflow tract just below the aortic valve.  This obstruction is a result of a structural or anatomic narrowing that is heritable in nature.  This lesion ranges from inconspicuous nodules or ridges to thick fibrous rings that encircle the entire left ventricular outflow tract, and can involve a portion of the mitral valve apparatus.  When the obstruction is moderate or severe, left ventricular hypertrophy (thickening) is a secondary finding.  Subaortic stenosis is typically suspected when there is a murmur over the aortic region. The definitive diagnosis is made via echocardiographic study.  During the echocardiogram care must be taken to accurately measure the velocity of the blood flow through the stenotic area.  This allows the cardiologist to determine the severity of the disease.  Treatment for subaortic stenosis ranges from oral medications (beta blocker therapy) to invasive procedures such as balloon valvuloplasty. 
   
   Subaortic stenosis is more common in dogs than cats.  The breeds most commonly affected with suboartic stenosis are: Newfoundlands, Golden Retrievers, Rottweilers, Boxers, Samoyeds Bulldogs, and German Shepherds.

7. Pulmonic Stenosis
   Pulmonic stenosis is a congenital narrowing of the right ventricular outflow tract.  This narrowing typically occurs at the pulmonic valve in small animals.  In most dogs this narrowing is due to abnormal development of the pulmonic valve (valvular dysplasia).  In  English Bulldogs and Boxers this narrowing may be due to an abnormality in the coronary arteries.  When the obstruction is moderate or severe right ventricular hypertrophy (thickening) is a secondary finding. Pulmonic stenosis is suspected when there is a murmur over the pulmonic region.  The definitive diagnosis is made via echocardiographic study.  With Bulldogs and Boxers additional testing is required (catheter studies or MRI) in order to determine if an abnormal coronary is responsible for the narrowing.  Balloon Valvuloplasty is not an option if abnormal coronary anatomy is the underlying cause for the stenosis.  Treatment for pulmonic stenosis ranges from cardiac medications to invasive procedures such as balloon valvuloplasty or patch graft surgery.
   Pulmonic stenosis is more common in dogs than cats.  The breeds most commonly affected with pulmonic stenosis are: Terriers (West Highland White, Scottish, Wire-haired Fox, Yorkshire), Miniature Schnauzers, Chihuahuas, Boxers, Samoyeds, Bulldogs, Keeshonds, Mastiffs, Bullmastiffs, and Beagles.

What types of medications are used to treat cardiac diseases in veterinary medicine?

Vasodialtors

Vasodialtors are medications that lower the blood pressure in arteries and veins.  This can improve cardiac output and decrease the formation of edema or effusions.  The most common vasodilator used in our practice is Enalapirl.  Enalapril is in a class of drugs called ACE-inhibitors, which affect both arteries and veins.  In some cases, more potent arterial vasodilators are used.  Similar medications are used to treat systemic hypertension (high blood pressure).

Digoxin

Digoxin is in the digital glycosides class of medications.  These medications have been used in some form for hundreds of years in human medicine.  Despite this long history, the exact pharmacology still may  not be completely understood. Through multiple mechanisms, Digoxin has several beneficial effects on the diseased heart.  These include improvement in heart muscle strength, reduction in heart rate, suppression of certain arrhythmias and a reduction in alterations of blood pressure.

Diuretics

Diuretics are fundamental in the treatment of congestive heart failure.  By increasing the amount of fluid lost in the urine, diuretics reduce the formation of edema or effusions.  Furosemide, also know as Lasix or Salix, is the most commonly prescribed diuretic. Diuretic use can lead to electrolyte abnormalities and dehydration.  Routine blood tests are required for animals receiving diuretics to avoid these complications.

Anti-arrhythmics

There are several different classes of anti-arrhythmic medications.  By blocking various cellular channels or receptors, these medications help reduce the formation and propagation of abnormal cardiac rhythms.

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