Cat Disease Heart In
Cat disease heart in – list of possible heart problems in cats
The cat is extremely fortunate in that it rarely suffers from heart disease.
Valvular incompetence, cardiac hypertension and arteriosclerosis – all comparatively common in the dog and in humans – are seen only in the late stages of senility as part of the natural dying process. All combine to make the end rapid and comparatively painless.
Thrombosis in the main artery supplying the hind legs has occasionally been recorded. It causes pain and paralysis. In oriental breeds, heart defects may be hereditary; these can be detected by chest X-rays after injecting a special radio-opaque material intravenously. But, all in all, heart problems in cats are so rare.
Heart Problems in cats
A diseased heart is less able to pump blood, and may deprive the body of life giving oxygen and nutrients and/or allow fluid to “back up” in various parts of the body. Major signs of oxygen deprivation are weakness, perhaps most noticeable after exercise, and fainting, which may look like a seizure, while fluid in or around the lungs usually causes breathing difficulty. Almost any form of heart disease in cats can cause sudden death.
Congenital heart defects (which the animal is born with) in cats are usually “plumbing problems” that either disrupt or divert the normal flow of blood through the heart. Possible defects include openings where there should be none, openings that are too small, valves that leak, blood vessels that are in the wrong place or are too narrow, and vessels that are supposed to shut down at birth but that fail to do so.
Weakness, fainting, breathing difficulty, or stunted growth are often seen in cats with congenital heart defects. With few exceptions, the end result is heart failure. Treatment and outcome depend upon the nature of the defect.
Hypertrophic cardiomyopathy is a disease of the heart muscles whereby, for unknown reasons, the muscle walls of the left ventricle become thickened and ultimately compromise the heart’s ability to pump blood. Congestive heart failure with pulmonary edema (fluid in the lungs) is a common consequence.
In addition, blood clots tend to form within a chamber of the heart. If one breaks free, it circulates rapidly and lodges in an artery, commonly one supplying blood to the rear legs; sudden paralysis of the rear limb(s) is the repercussion.
Some cases of hypertrophic cardiomyopathy can be diagnosed early if the veterinarian detects abnormal heart sounds during a routine physical examination; ultrasonic examination of the heart confirms the diagnosis. If treatment is started early enough, the prognosis for long-term survival is guarded to fair for most cats. Medications are given to control pulmonary edema, the strength of heart muscle contractions, and the formation of blood clots.
Heartworm disease is commonly considered a disease of dogs, but the offending parasite (a worm called Dirofilaria immitis that is transmitted in its larval stage by mosquitoes) can infect cats as well. Some heartworm-infected cats have no problems at all; some just act lethargic or lose appetite and weight; some suffer temporary or intermittent vomiting, coughing, or breathing difficulty; others die suddenly. Fortunately, many cats are able to fight off infection by themselves.
When a cat is bitten by a mosquito carrying the larval parasites, the larvae are carried along with mosquito saliva through the bite hole into the cat’s body and continue to mature as they migrate through the tissues. Eventually, they reach the heart and pulmonary vessels, stimulating an intense inflammatory reaction in the lungs that often results in rapid breathing, coughing, or vomiting.
These signs usually abate after several weeks, but in some cases they may persist. After the initial episode, mature worms usually cause few signs of disease. But it is after about two years, when the worms die, that a cat exhibits some of the most severe signs of heartworm infection-very severe coughing, marked breathing difficulty, or sudden death.
There is no safe way to kill the worms, but they do not live as long in cats as they do in dogs, so many cats that experience problems as a result of infection may be free of disease after a period of time. Coughing and vomiting caused by the parasite usually can be controlled by an oral cortisone-like medication.
A preventive medication that kills the larvae before they reach the heart is recommended for routine use in areas where heartworm disease exists. Heartworm has been seen in almost all parts of the United States and southern Canada, but it is most prevalent on the east coast of North America, in the southern United States, and in the Mississippi River valley.
High blood pressure (systemic hypertension) is common in elderly cats. It is almost always secondary to some other disease, especially kidney disease and hyperthyroidism. Left untreated, hypertension can cause enlargement of the heart, worsening of kidney disease, seizures, and sudden blindness. Treatment of the condition primarily relies on managing the underlying condition; if necessary, antihypertensive medications similar to those used in people are given orally.
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Cat Anatomy Heart and Lungs
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Cats have typical mammalian respiratory and circulatory systems. The air they take in through the mouth and nostrils travels down the windpipe (trachea) to the lungs.
Encased in the protective rib cage and separated from the abdomen by the diaphragm, the heart and lungs then work together to circulate oxygen, via the blood, throughout the body.
Conducted along an intricate system of arteries and veins, blood distributes oxygen, nutrients, and disease-fighting agents and takes up carbon dioxide and other waste products.
When the blood makes its way back to the lungs, the blood vessels of the circulatory system and the branches of the respiratory system (called bronchi and bronchioles) make a vital exchange of newly inhaled oxygen for carbon dioxide to be exhaled.
The feline heart is well adapted to a predatory lifestyle, capable of accelerating from a resting heart rate of about 150 beats per minute to more than 240 beats per minute (four beats per second) to provide the circulation needed for sud¬den bursts of speed.
Cat Anatomy Heart and Blood Vessels
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The cat has a comparatively small but exceptionally strong heart. As in all animals the heart is a powerful pump comprising the strongest muscle in the body.
It is surrounded by a serous membrane or sac called the pericardium, which under normal circumstances contains a small quantity of lubricating fluid called the pericardial fluid.
The heart comprises two lower chambers with extremely thick walls (the right and left ventricles) and two upper cavities with slightly thinner walls (the right and left auricles). The left-sided chambers are both larger than the right.
As the blood passes round the body, it collects carbon dioxide from the various tissues and this is carried by the veins to the right auricle.
It then passes through a valved opening into the right ventricle and from there the thick walls pump it to the lungs through the pulmonary artery.
In the lungs the carbon dioxide is expelled as the cat breathes out, and oxygen takes its place as the cat breathes in. The oxygenated blood is then carried back to the left auricle by the pulmonary vein. From there it passes through another valved opening into the left ventricle – the most efficient pumping chamber ever created.
The left ventricle pumps the oxygenated blood through the arteries round the entire body (see diagram). The process is continuous, starting when the kitten is in the embryo state within the mother’s womb and stopping only when the cat dies.
Cats have 3 blood types: A, B and AB. Most cats are type A, but incidence of types varies geographically. Virtually all cats in Switzerland are type A, for example, but this drops to 97% in Britain and 85% in France.
Many pedigree breeds are almost exclusively type A, but others show varying levels of type B. Type AB is extremely rare and not linked to breed.