Lee
Stuart, FL

A heart murmur is a description of how the heart sounds when a veterinarian listens to it. The presence or absence of a heart murmur does not always correlate with the presence or absence of heart disease.

A heart murmur signifies turbulent flow of blood through the heart. Under normal circumstances blood flows through the heart smoothly and soundlessly. In animals with heart murmurs the blood does not flow as smoothly, and this causes a shushing noise that is called a heart murmur.

Blood flowing through the heart is similar to water flowing through a hose. A kink or irregularity in the hose can lead to a shushing noise as the water flows through. Any irregularity in the structure of the heart or the flow of blood through the heart causes a similar shushing noise.

Heart murmurs come in two broad categories: non-pathological and pathological. Non-pathological heart murmurs are caused by benign hereditary or developmental anomalies and other harmless irregularities in the structure (but not the function) of the heart.

Pathological heart murmurs are caused by leaky valves, irregularities in heart muscle structure, or anatomical irregularities that compromise heart function.

Animals like MidgeyGirl that develop heart murmurs at a young age often have non-pathological murmurs. Animals that develop heart murmurs late in life most often have pathological heart conditions.

However, there is absolutely no way to tell whether a murmur is pathological or non-pathological simply by listening to it. Diagnostic tests are needed to determine whether disease exists and whether medications are necessary.

A combination of chest X-rays and ultrasound of the heart (known as echocardiography) almost always reveals whether heart pathology is present. Basic blood tests (and a special blood test called pro-BNP) also are useful.

I recommend that your vet perform these tests on MidgeyGirl. Hopefully the results will put your mind at ease.

Go to my website for more information on heart disease in pets.
Cats: http://drbarchas.com/feline_heart_disease
Dogs: http://drbarchas.com/canine_heart_disease

Photo: Lola’s heart looks good!

Medical technology: A new, low-cost design for an artificial heart takes its inspiration from an unusual source—the cockroach

EVOLUTION has favoured cockroaches above human beings, at least when it comes to the functioning of the heart. A cockroach’s heart will continue to beat even when one of its chambers has failed; in similar circumstances, a man will die. Now a team led by Sujoy Guha of the Indian Institute of Technology, Kharagpur, has created an artificial human heart based on a cockroach’s, which they believe will be unusually robust and affordable.

A cockroach’s heart is a tube that runs the length of its body. It has 13 chambers, linked like a string of sausages. As each chamber contracts, the blood within is pumped to a higher pressure. Each successive chamber increases the pressure. A human

or feline or canine

heart, by contrast, has four chambers. Two of these pump blood to the lungs, where it picks up oxygen, then the other two pump this oxygenated blood throughout the body. One of these four chambers—the left ventricle—contracts most strongly to pressurise the blood.

The artificial hearts developed so far have mostly mimicked human ones. The first devices, developed in the 1950s and 1960s, were large machines placed on trolleys next to the patient and attached by tubes. Modern artificial hearts are less cumbersome, but they are still rather unwieldy because they use compressed air to pump the blood and are powered by heavy batteries. They are used temporarily, usually for a few days or weeks, until a real heart is available for transplant.

Instead of trying to mimic the action of the left ventricle, Dr Guha’s design uses a multi-step approach borrowed from the cockroach. His device, made from plastic and titanium, is the same size as a human heart but with five chambers arranged like the layers of an onion. Each chamber acts in succession to increase the pressure of the blood. The contraction of each chamber is controlled by a motor driven by bulky batteries. The artificial heart is being tested on goats, with human trials scheduled for next year. If these are successful, the device could be on the market in three to five years.

The multi-step approach makes this artificial heart much cheaper to build than those that use compressed air to pump the blood. Dr Guha says it would cost $2,000-2,500.

Add in the costs of protection from liability lawsuits, and I’ll bet the new artificial heart will come in for $50,000 or so.

This article nearly inspired me to make another 30 year prediction for the record: that artificial hearts will be available for cats and dogs by 2039. But, although I am excited by advances in artificial heart technology, I am not going to make that prediction.

Instead, I predict that within 30 years stem cell technology will allow veterinarians to grow new hearts for cats and dogs from their own tissues.

Melanie
North CA

Heart disease in cats generally is caused by a syndrome called cardiomyopathy. The muscle of the heart does not function properly in cats with the syndrome. This can lead to heart failure or other serious complications including sudden death.

Feline heart disease is much less common now than several decades ago. That is because one of the causes of heart disease in cats was discovered to be a dietary insufficiency of an amino acid called taurine. Taurine is now routinely added to most feline diets.

Hereditary causes are involved in most cases of feline heart disease in current times. Breeds such as Maine Coons and Persians have known predispositions to cardiomyopathy. However, the syndrome can strike any breed of cat. It also affects non-purebred individuals.

Modern genetics hopefully will dramatically reduce the incidence of feline cardiomyopathy in the near future. I, for one, would be very happy never to see another case of it. The disease is not highly treatable and it frequently strikes young cats who otherwise would have most of their lives ahead of them.

Charmaine
Mendocino, CA

Dogs generally make goose-like noises when they cough. Since foreign objects lodged in the nose usually cause sneezing, it isn’t likely that your Yorkie has something stuck up his nose.

In young dogs, kennel cough (also known as infectious tracheobronchitis) is a common cause of goose-like honking. Kennel cough is a contagious disease that almost never is life-threatening. Most cases are self-limiting (which means that they resolve on their own without treatment).

In older small dogs such as Yorkshire Terriers, a syndrome called collapsing trachea frequently leads to a honking cough. Collapsing trachea occurs when the firm rings supporting the wind pipe begin to weaken. It leads to a chronic tickle in the throat.

Heart disease is another common cause of coughing in older small dogs. Yorkies sometimes develop leaky heart valves as they age. This causes fluid to build up in the lungs which leads to coughing.

Several less common causes of coughing also are possible. These include, among others, pneumonia, bronchitis and heartworm. Visit my website for more information, or, better yet, go to the vet for a proper diagnosis.

Photo: Minnie at the beach. No sign of coughing.

I was quite excited when Discovery CME, an organization that offers online continuing education for physicians, confused me for an MD and sent me their schedule. Among their offerings is a program that seemed right up my alley. The program is entitled “Pets and People: The Power of the Health Connection.” You can watch it online if you have a high speed connection.

The program is intended to be educational material for human physicians. I found this surprising (and, on some levels, disturbing) because the narration and theme of the program make it seem much more like an after-school special than a serious scientific work.

However, it makes solid points.

The above list does not even come close to being complete. If you want to read more about the ways in which having a pet benefits human health, check out the humanhealth tag on this blog. As well, you can find more information The Power of Paws, a website dedicated to spreading the word.

There are two major forms of heart disease in dogs. Small breeds are prone to valve disease. Valve disease causes the blood to flow incorrectly through the heart and lungs. Large breeds are prone to cardiomyopathy, a syndrome in which the muscles of the heart lose the ability to function normally. Either condition can lead to heart failure and death.

The mainstays of diagnosing canine heart disease have been physical exam, evaluation for irregular heart sounds known as murmurs, X-rays and echocardiography (ultrasound of the heart). Echocardiography is especially effective at diagnosing heart problems. However, in many cases the problem is not detected until it has been present for a very long time. And, as with all medical conditions, treatment for canine heart disease is most effective if the problem is detected early.

Fortunately, a paper in the May 15, 2008 Journal of the American Veterinary Medical Association describes a new test that may soon become available to identify dogs with heart disease. The test would be a blood test that could be performed routinely on at-risk breeds.

The test would involve measuring the level of a peptide (a very small protein) in the blood. A recent study demonstrated that blood levels of the peptide reliably predict the presence and severity of heart disease in dogs.

It may be several years before any test involving the peptide is available for veterinarians. However, it is encouraging to know that in the future it may be possible to diagnose heart disease earlier and more easily in our canine friends.

The paper discussed in this post is Oyama, et al J Am Vet Med Assoc 2008;232:1496-1503

Image credit: Heikenwaelder Hugo. Image licensing information: CC
Image confession: it is a human heart. But the canine heart is anatomically similar.