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Heart Disease in Dogs, Cats, and Other Pets  

It surprises some owners that heart disease is common in cats and dogs...just like in humans.  And just like in humans, the heart is a mechanical-electrical pump made out of living tissue and is prone to not only to all the biological hazards affecting cells, but also to all kinds of mechanical, stretching, leaking, and electrical mishaps, pressure problems, clogs, and disasters that affect non living tissue.

Unlike with diarrhea or skin problems, most pet owners don't know or even suspect their pet has heart disease, but veterinarians often detect the problem during routine physical exams early enough to make a wonderful difference to the longevity and well being of the pet.

This is one of several major reasons for making sure your pet has a good check up at least once a year.

Sometimes your vet will pick up on early heart disease even when there are no obvious symptoms yet because you're the wonderful type of pet owner that allowed your vet to spend a little extra for pre-anesthetic blood work and/or EKG monitoring prior to and during a surgery or dental cleaning procedure that was needed.

And, of course, heartworm disease ... the most common type of heart disease... is frequently detected long before obvious symptoms occur because of the routine testing done in just about every clinic in those parts of the country where heartworm is prevalent.

One last introductory comment:  Just like in humans, heart disease is associated with genetic factors but also with


Exam and History:
There are lots of clues on history such as being tired after a little bit of exercise, coughing after exercise and so forth.  

We will be giving your pet a good general exam that will include listening carefully to your pet's heart and lungs, feeling the quality of the pulse, checking the color and nature of the mucus membranes, checking the tiny vessels in the eyes, palpating the abdomen, and maybe rechecking everything after exercise.

We will also be asking a lot of questions that will help us with the diagnoisis and hopefully prevent us from going down some expensive false trails.  (such as mistaking indigestion for heart disease and vice versa)

It's interesting that certain breeds are more likely to have certain types of heart disease:

Murmers:  Cockers, Poodles, Schnauzers, Dachshunds, Chihuahuas, Pomeranians, and Min. Pinschers

Myocarditis:  Boxers, St Bernards, and German Shorthair Pointers

Cardiomyopathy:  large breeds of dogs

Heart base tumors:  Boston Terriers, Boxers, and English Bulldogs

Various Congential Heart Problems:  Poodle, Collies, Poms, Sheperds, Eng. Bulldogs, Schnauzers, Pointers, Keeshonds, Fox Terriers, Irish Setters, and Weimaraners.

Once heart disease is suspected, your vet will discuss and offer and least some of the following laboratory and imaging choices:

A.  Rule out heartworm disease with an elisa test: 

B.  CBC and Chemistry;  this is important because so often heart disease is seen in association with other diseases...especially kidney and liver diseases. 

C.  Radiographs; to see if the heart is enlarged typical of certain types of heart disease, to see if there are tumors, to see if the lungs are very congested, and to see if there is fluid around the heart. 

D.  Urinalysis:  This test is not likely to tell us anything specific about the heart, but it's included in the work up of  pets suspected of serious disease. 

Why?  Because most serious diseases also involve other organ systems and this fairly inexpensive test of urine gives us a good feel for the heatlh of the kidneys and bladder as well as hints about pancreatic, liver, and gall bladder health.  It helps with our asscessment of tissue hydration too.

E.  EKG:  EKG's help us rule out cardiac blocks and arrthymias, electrical conduction problems of the heart, and also are pretty good at indicating cardiac enlargement.

If your vet, like me, is not expert at reading EKG's...or chest x-rays, for that matter, with the modern miracle of the digital age, we can have an expert read your pet's EKG or X-ray from a remote location through the phone lines!

F.  Echo, Ultra Sound, Angiograms, MRI's, Cat Scans, and other types of Imaging:  All this is now available in veterinary medicine, although usually a trip to a specialist facility is necessary.

As you might suspect, while many heart problems can be greatly improved with inexpensive medicine and nutritional support, the best available testing and treatment for heart disease can be quite expensive.

I mention this for three reasons:

  One:  To prepare you to think realistically.  Heart disease is fairley common and often stikes without much warning.

  Two:  To motivate you to take the trouble and relatively minor expense of providing a good lean diet, lots of exercise, and heartworm preventive.

  Three:  To consider Pet Health Insurance.  It sure is nice to have when your beloved pet needs it.

Once a Tentative Diagnosis is Made, your vet will discuss these treatment options:

1.  Consider referral to a specialist for heart disease...Your vet will give you an honest accessment of his or her skill level in treating any serious disease.  Don't expect your general practioner to be an expert in everything...especially a complex disease like heart disease where highly specialized equipment is often needed and where new, potentially dangerous, medications are frequently being introduced.

2.  At our clinic,  if  you elect to let me treat your dog after making a tentative diagnosis of heart disease, here's what we'll consider trying:

A.  Nutritional support.  We'll recommend taking advantage of one the several superior diets made especially to minimize cardiac problems.

B.  Weight Loss if appropriate...Many heart disease patients are way too fat.

C.  Furosimide tablets as needed to control coughing and congestion.  This is a diuretic and will make your dog urinate and drink more but often works well in relieving the fluid load in the lungs associated with heart disease.

D. Digoxin tablets:  this poison, given in tiny amounts helps improve cardiac function.   This medication is not tolerated by many pets (causes nausea etc), so we will start out with a small dose and work up.

E.  Blood Pressure tablets:  Ace Inhibitors (Enalapril or  Captopril)  greatly reduce the work load of the heart by  causing dilation of the blood vessels.  Possibly dangerous if your pet also has kidney disease.  Another reason to do blood work and an urinalysis to check other organ systems.

F.  Potassium or Multivitamins; loss of potassium is a problem with both heart disease and the medications used to treat heart disease.

G.  Aspirin; small amounts help prevent secondary problems such as blood clots that are sometimes part of the cardiac disease syndrome.

The aspirin dose we will be recommending is small enough that problems such as GI inflammation is not likely.

H.  Beta Blockers decrease outflow obstruction common in heart disease and are often recommended by cardiac specialists, especially in cardiomyopathy.

I.  CoEnzyme Q10:  a neutriceutical highly touted by the people that sell it for improving cardiac and vascular health.  CoEnzyme Q10 does seem to be helpful, but beware that it hasn't been accepted yet as safe and effective by cardiac specialists, the FDA, etc.

It's hard to get approval in the medical industry for neuticeuticals and despite lots of testimonials for these medications it's very hard to get honest information about them.  I'm presently a believer in the usefulness of CoEnzyme Q10  but based on pretty flimsy medical evidence.  (See my comments on the neutriceutial business in the medication section of this site.)

Despite these warnings, supplementation with coenzyme Q10 has resulted in dramatic increases in cardiac contractility in humans with cardiomyopathy. Coenzyme Q10 is a member of the electron transport chain essential in myocardial energy production. Clinical trials examining the efficacy of coenzyme Q10 in the dog are underway.

J.  Frequent rechecks.  Heart disease and the medications used to treat heart disease both merit frequent rechecking and adjusting. 

K.  Again...consider referral.  Especially if results are poor.


"When it comes to heart disease, regular visits to your veterinarian could mean the difference between life and premature death," says Joanne Bicknese, DVM, Manager, Technical Services for Merck AgVet, the animal health division of Merck & Co., Inc. "Dog owners may not realize that their pets are susceptible to many forms of heart disease. In most cases, heart disease can be successfully managed with early detection and treatment".

Heart Failure
One major threat to your dog's health is heart failure. Of the dogs in the United States examined annually by a veterinarian, approximately 3.2 million have some form of acquired heart disease and may be in heart failure.

Heart failure results from the heart's inability to pump blood at a rate required to meet the body's needs. While continuing to work harder to pump blood, further heart damage can occur.

Although some of the early stages of heart failure in dogs have no visible signs, heart failure can be diagnosed through a clinical evaluation by a veterinarian. Dogs with mild to moderate heart failure typically experience heart enlargement, coughing, lethargy and difficulty breathing.

Severe heart failure is characterized by difficulty breathing (even at rest), fainting, profound intolerance to exercise, loss of appetite and weight loss.

"Too often, dog owners do not take their dogs to visit the veterinarian until they are displaying severe signs of heart failure, and by then it may be too late," says Dr. Bicknese.

"When heart disease is detected in your dog, your veterinarian can recommend a schedule of regular visits and discuss a treatment plan that can help."

Overall Good Health
In addition to safeguarding your dog's heart, there's a lot you can do to keep your dog happy and in top shape. Ensure that your dog gets a moderate amount of exercise on a regular basis and has a balanced diet. An obese dog may have a harder time staying healthy.

Avoid the heartbreak of seeing your family's best friend fall ill. Proper care and veterinary supervision can help you watch your dog grow to a "hearty" old age.

Remember that this information is not intended to be a substitute for taking your beloved pet to your veterinarian. 
It takes experience and the right tools of the trade to determine whether a problem is likely to respond to simple treatment and a little love or require a full medical commitment to save the patient.not only is this information not intended to help you treat serious pet health problems at home; I am hoping these pages will reinforce your awareness to just how complicated and variable diagnostic and treatment choices can be. Veterinary Medicine is a bargain; take advantage of it.

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Diseases of the heart muscle are less common than disorders of the valves. Dilated cardiomyopathy is, however, the second most common from of canine heart disease. Hypertrophic cardiomyopathy, although a common condition in cats and people, is rare in dogs; so, too, is myocarditis. The risk of heart diseases is inherited, particularly in certain breeds. It can be reduced by breeding from dogs whose families are free of disease.

DILATED CARDIOMYOPATHY
This condition, also called DCM, affects relatively young dogs, usually under 7 years old, and sometimes as young as 2 years of age. In Cocker spaniels it may be associated with hypothyroidism, a condition in which a dog's own immune system attacks the thyroid gland, resulting in diminished thyroid hormone production. DCM may also be associated with immune system in the Doberman Pinscher. The breeds most commonly affected include the Boxer, Doberman Pincher, Irish Wolfhound (all high-risk), and also the Afghan Hound, Great Dane, Old English Sheepdog, and St. Bernard. The condition now is also being diagnosed in smaller breeds, including Cocker spaniels and Dalmatians. DCM affects more males and females.

Affected dogs are lethargic, tire easily from routine exercise, and often go off their food and lose weight. They may have a cough, especially at night. Congestive heart failure develops; as a result, fluid accumulates in the lungs and/or in the belly, causing the abdomen to swell. Both Boxers and Dobermans may die suddenly without showing any previous signs of illness.

Diagnosis
An ECG will show changes in the heart's rhythmic contraction, while a chest X-ray will reveal that that the heart has become enlarged and dilated (expanded). Echocardiography will confirm that the heart wall is thin and the heart chambers are enlarged.

Treatment
The dog is given treatment for congestive heart failure. Diuretic drugs such as spironolactone or furosemide diminish the buildup of fluid in the lungs and abdomen, while ACE inhibitors and a new drug, pimobendan (Vetmedin), improve the heart function and circulation. There is nutritional logic in supplementing the diet with taurine and L-carnitine, although the benefit of these nutrients is still being studied. The long-term outlook for an affected dog is rather poor, although the use of pimobendan has increased survival time threefold in Doberman Pinchers.

HYPERTROPHIC CARDIOMYOPATHY
In this condition, the heart wall becomes thickened. It usually affects the ventricles (the lower chambers of the heart). As the muscle thickens, it reduces the space inside the heart for blood. The most common sigh is reduced exercise tolerance.

Diagnosis and Treatment
Hypertrophic cardiomyopathy is diagnosed by echocardiography. Treatment with the calcium channel blocker drug diltiazem appears to prolong life expectancy. strenuous exercise should be avoided.

MYOCARDITIS
This rare inflammation of the heart muscle has many possible causes. When canine parvovirus infection first occurred, the virus caused a fatal form of myocarditis in puppies, but this cause is now extremely rare. Other causes of myocarditis include canine distemper virus; Lyme disease; other viral and bacterial infections; and trauma.

Diagnosis and Treatment
Clinical signs of myocarditis include lethargy, fainting and heart rhythm disturbances. The treatment for this condition is similar to that for congestive heart failure.

Join
Yahoo Groups Canine Heart Health List
 A Yahoo list group for owners living with a dog with heart disease, a great source for information and support.