Dog heart disease – blood pressure
Dog Heart Disease
Dogs are the same as humans when it comes to heart disease. It can be either present at birth – a congenital faulty heart condition, or acquired – often developing over time during middle age and affecting many older dogs. Both types can end up with the same serious result which a condition is called heart failure.
Regular visits to your veterinarian could mean the difference between a long life and premature death. Dogs are susceptible to many forms of heart disease, but in most cases, heart disease can be successfully managed with early detection and treatment, and he can live a decent and happy life. Although there is no cure for most heart disease in dogs, new treatments are available. Success of treatment depends on various factors, but early detection is always best. By following your veterinarian’s recommendations, you can help your dog live a longer, more comfortable life.
Heart disease in dogs is often caused by defects in the valves or the heart muscle (myocardium), and less commonly by tumors.
The most prevalent type of acquired heart disease, Chronic Valvular Disease (CVD), is also known as mitral regurgitation, mitral valve disease and valvular insufficiency, among other names. In CVD, the heart valves gradually lose the ability to close effectively, causing abnormalities in blood flow.
The second most common kind of acquired canine heart disease, Dilated Cardiomyopathy (DCM), caused the muscular walls of the heart to become thinned and weakened, and the chambers to dilate. When the heart muscle becomes dilated it results in a reduced output of blood. Dilated cardiomyopathy (DCM) means the heart muscle becomes dysfunctional over time; however, there are drugs available that can help treat DMC.
Both CVD and DCM result in heart failure -which is a major threat to your dog’s health. 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.
Dogs with heart failure may retain salt (sodium chloride) and water in their bodies, and this leads to fluid retention. Fluid may accumulate in the lungs and in the abdomen, leading to coughing, difficulty in breathing, and abdominal distension. If the heart is not working as an efficient pump, the amount of blood circulating to the body will be decreased, causing fatigue, weakness, and pale-looking gums.
Signs of heart failure include:
– Frequent coughing or hacking
– Lack of energy and stamina
– Edema (swelling)
– Signs of poor circulation
– Irregular and rapid breathing
– Decreased appetite and weight loss
– Shortness of Breath
– Excessive Weakness (little or no desire to exercise – resist going for walks or runs)
– Abdominal Swelling (bloated appearance from fluid buildup)
– Heart: Impaired pumping ability
– Kidneys: Sodium and water retention
– Lungs: Fluid build up
– Veins and Arteries: constricted blood vessels and increased resistance to blood flow
Some of the early stages of heart failure in dogs have no visible signs, and need to 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.
Your veterinarian may ask you for specific information about your dog before performing a thorough physical examination, and he may want to do a series of tests. Testing is very important for early detection of heart disease in dogs.
Once heart disease is suspected, your vet will discuss and offer some of the following laboratory and imaging choices:
– CBC and Chemistry is important because often heart disease is seen in association with other diseases such as kidney and liver diseases.
– Radiographs (X-Ray) to see if the heart is enlarged which is typical of certain types of heart disease, to see if there are tumors, if the lungs are very congested, and to see if there is fluid around the heart.
(This test is not likely to tell anything specific about the heart, but it’s included in the work up of pets suspected of serious disease because most serious diseases also involve other organ system. This fairly inexpensive test of urine gives a vet a good feel for the health of the kidneys and bladder as well as hints about pancreatic, liver, and gall bladder health, along with helping on an assessment of tissue hydration.)
– EKG’s help rule out cardiac blocks and arrthymias, electrical conduction problems of the heart, and also cardiac enlargement.
– Echo, Ultra Sound, Angiograms, MRI’s, Cat Scans, and other types of Imaging
– The veterinarian will also test to rule out Heartworm Disease.
Treatment for heart failure may include feeding a low sodium diet, restricting exercise, and giving your dog one or more types of drugs. These drugs are used to increase the strength of contraction of the heart muscle, encourage water loss in the urine, and dilate the blood vessels so the heart can more easily circulate the blood.
After your vet carefully assesses your dog’s individual needs, and you commit to looking after your dog properly at home, he may be able to lead a relatively comfortable life.
Your veterinarian can recommend a schedule of regular visits and discuss a treatment plan that can help.
In addition, there is 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, because an obese dog may have a harder time staying healthy and any extra weight may put more stress on the heart and lungs. If your dog is overweight, you may be advised to try a low-calorie diet.
A low sodium diet may help to minimize fluid retention in your dog and stop him from coughing and feeling uncomfortable. Special diets for dogs with heart disease are
expertly formulated to ensure that all your dog’s nutritional needs are met. They may also be supplemented with the extra B vitamins that are lost in the urine if your pet is on diuretic drug therapy.
Animals with heart disease may have a decreased appetite from feeling unwell and from
the drugs they need to take. So special diets must not only benefit their health, but must also taste good. Your vet will work with you to encourage your dog to eat an appropriate diet. Be sure to feed the prescribed diet as your vet advises, and only to the affected dog if there are multiple dogs in the home.
Remember not to feed your dog any snacks or treats unless your vet says this is okay,
because these may contain a higher level of sodium than your pet needs.
The Bottom Line:
– Many of the heart problems that affect humans can also affect your pet.
– Pacemakers are available for animals and work much the same way as those in humans to help regulate heart beats.
– If drugs or other treatments fail, heart surgery is available, but it tends to be very expensive and the age of the animal is always a consideration.
– New medicines, radiology, injecting dye into arteries to locate blockage – all of these have helped tremendously in treating heart problems.
– Heartworms occur when a mosquito bites a heartworm-infected animal and then bites a non-infected dog or cat. Worms several inches long can grow inside the heart muscle and will cause illness or death if left untreated.
– Chagas disease is another heart ailment caused by a parasite and causes heart abnormalities, but it can be successfully treated with drugs.
– It’s important to remember that pets that do have heart trouble may need to modify their daily routine, but they often can still have a reasonable life span.
Blood Pressure in Dogs
The body has a complex control system that maintains blood pressure within a normal range. Your veterinarian will refer to diastolic and systolic pressure – these two values represent the peak (systolic) and trough (diastolic) of the pressure levels that occur with each contraction and relaxation of the heart.
When the overall pressure within the blood vessels becomes high, it is called "systemic (affecting the whole body) hypertension," or "high blood pressure" – and usually develops gradually. Problems from high blood pressure arise when a blood vessel gets too small for the high pressure flow going through it.
The circulatory system reaches every square inch of the body, so the effects of the pressure buildup in the blood vessels are far-reaching. Diagnosis of systemic hypertension may require an in-depth evaluation of your animal’s internal health status.
Signs may include:
– Changes in the eyes such as sudden blindness when blood vessels rupture in the back (retina) of the eye or the retina detaches
– Blood in the urine from kidney damage
– Bloody nasal discharge
However, many animals with high blood pressure show no signs of it, and the only way to diagnose it definitely is to measure the pressure in the circulatory system.
One of the big problems with diagnosing high blood pressure in animals is obtaining an accurate blood pressure measurement. Just as humans get nervous at the doctor’s office where blood pressure measurements reflect stress rather than their normal levels, the same phenomenon occurs in some animals when they see the veterinarian, and can lead to falsely elevated blood pressure readings. But this will be taken into account when reading blood pressure. Overall, most pets are able to maintain normal blood pressure in spite of being surrounded by hospital staff.
The veterinarian may perform diagnostic tests, such as blood work, urinalysis, and hormone assays (for example, thyroid hormone). Imaging studies such as radiographs (X-rays) or ultrasound (visualization of deep body tissues by recording ultrasonic waves) of the chest and abdomen may identify related problems.
There are numerous diseases in pets that are associated with high blood pressure:
– Chronic Renal (kidney) Failure
– Cushing’s Disease (an adrenal cortisone excess)
– Diabetes Mellitus (inability to properly reduce blood sugar)
– Acromegaly (growth hormone excess)
– Glomerular Disease (a disease of the kidney filtration system)
– Polycythemia (an excess in red blood cells)
– Pheochromocytoma (an adrenaline secreting tumor of the adrenal gland)
In humans, high blood pressure is frequently considered "primary" meaning there is no other disease causing it. However, in animals primary hypertension is unusual because there almost always is another disease causing it and if routine screening does not identify the problem, more tests may be in order. If a pet has one of the above diseases conditions, blood pressure is generally checked. It has recently been recommended that older pets have their blood pressure checked whenever they have a physical examination. If you own a pet over age nine, be sure to ask for a blood pressure check if one has not been recommended to you.
The other time high blood pressure is discovered is when it makes its presence known. This usually means some degree of blindness or some other obvious eye problem. The retina of a hypertensive patient develops tortuous looking retinal blood vessels. Some vessels may even have broken showing smudges of blood on the retinal surface. Some areas of the retina simply detach, or even the entire retina detaches. With early identification, some vision may be restored. Do not let minor vision changes go unreported. Let your veterinarian know if you think your pet’s vision is not normal.
Retinal changes can be complicated to interpret. Do not be surprised or alarmed if your veterinarian recommends referral to a veterinary ophthalmologist.
Measuring Blood Pressure in Pets:
Blood pressure measurement is performed similarly to the way it is in humans. An inflatable cuff is fit snugly around the foot or foreleg of the pet. Sometimes the base of the tail can be used. The cuff is inflated so as to occlude (block off) blood flow through the superficial artery. In humans, as the cuff is slowly deflated a stethoscope is used to listen for the point when the blood pressure is adequate to pump through the partially occluded vessel. This point on the pressure gauge is the "systolic" blood pressure. The cuff is further deflated until the vessel is open and no more sounds are made. This point represents the "diastolic" blood pressure.
However, in animals the stethoscope is not sensitive enough and an ultrasonic probe
must be taped or held over the artery. Using ultrasound, the sound of the systolic pressure is converted into an audible signal. It is not possible to measure diastolic pressure in a pet without actually placing a catheter inside an artery so vets make do with just a systolic measurement. In pets, this measurement should not exceed 160.
Treating High Blood Pressure in Pets:
When hypertension is identified, a search for the underlying cause is indicated. It may be that controlling the underlying disease totally reverses the hypertension (especially true for hyperthyroid cats).
The treatment for systemic hypertension depends on the severity of the high blood pressure and the clinical signs. The animal usually is managed on an outpatient basis unless the condition has progressed to the point where serious complications, such as eye damage, are identified. Reducing salt intake may be recommended as part of the therapy.
Most animals with systemic hypertension require medication to lower their blood pressures. Medications commonly used include vasodilators that expand (dilate) the blood vessels and diuretics to remove excess body fluids. Sometimes a combination of medications may be needed in order to control the blood pressure adequately and to minimize any side effects.
Medications such as enalapril, amlodipine besylate, diltiazem, and spironolactone can be prescribed to improve your dog’s health.
When ocular (eye) disease is present, special eye drops may be required depending on how much bleeding is present in the eye and whether or not return of vision is likely.
An ophthalmology specialist may be especially able to help.
Salt restriction in the diet is a good idea. Your dog may benefit from a special therapeutic diet that your veterinarian can prescribe. This generally means a dry or canned formula
prescription diet if the pet will eat it or a diet limited to dry food if the pet will not accept prescription food. Appropriate home cooked diets may be designed through a veterinary nutritionist.
Hypertensive patients should be rechecked every two to four months to keep their blood pressure in a healthy range.
High blood pressure generally can be controlled with medications and if possible, correction of the underlying cause. As with most conditions, the prognosis for animals with systemic hypertension ultimately depends on the underlying reason for the high blood pressure. The prognosis for animals with hypertension due to kidney failure is generally poor. The prognosis is fair in animals with adrenal gland disease and generally good with thyroid disease. The most important aspect affecting the animal’s future is that the problem be identified before serious organ damage occurs. Once the elevated blood pressure produces wear and tear on the delicate blood vessels of the eye and kidney -permanent tissue damage is a concern.
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Canine Illnesses and Disease – Heart Disease in Dogs
Veterinarians Can Help Pets with Heart Disease
Cardiac Diseases of Cats and Dogs
High Blood Pressure (systemic hypertension) in our pets
VetMedCenter.com – Systemic Hypertension (High Blood Pressure)
Georgia Veterinary Specialists – Systemic Hypertension