Disease Ontology ID: DDTO:0001230

Disease Description: A condition where one of the valves of the heart does not open properly.

Inherit Mode: Pulmonic stenosis appears to be inherited as a polygenic threshold trait. This means that more than one genetic aberration contributes to pulmonic stenosis; a genetic test for identifying it does not exist at this time.

Disease Symptom: Pulmonic stenosis is usually suspected based on a veterinarian's detecting a heart murmur when listening to a dog's heart with a stethoscope. Murmurs may be caused by many, many disorders, including pulmonic stenosis, so it is important to know that just having a heart murmur (of any grade) is not definitive for pulmonic stenosis. If a heart murmur is detected and the veterinarian feels it could be due to pulmonic stenosis, he/she will recommend tests to confirm pulmonic stenosis or eliminate it from consideration. These tests are noninvasive and very accurate (see below), and they mainly help to answer two questions: "Is it pulmonic stenosis?" and if it is, "Is it severe enough that something needs to be done?".

Disease Cause: -

Disease Diagnose: The first indication of pulmonic stenosis is generally a heart murmur detected in a young dog (typically during puppy vaccine visits between the ages of 2 and 4 months). Much less commonly, dogs with severe pulmonic stenosis may develop symptoms such as abdominal enlargement -a bloated appearance to the belly, caused by fluid retention- or laboured breathing or collapse/fainting. Either way, a veterinarian's suspicion of pulmonic stenosis justifies doing thoracic radiographs (chest X-rays) and an echocardiogram (also called cardiac ultrasound, or sonogram of the heart). These tests help to pinpoint whether pulmonic stenosis is present and if it is, whether it is mild, moderate, or severe. Specifically, the echocardiogram can detect whether secondary changes such as thickening of the right ventricle or other distortion of the heart's structure has occurred, and the degree of strain under which the heart is forced to operate. The extra workload that pulmonic stenosis imposes on the heart is identified through Doppler ultrasound calculation of a pressure gradient between the right ventricle and pulmonary arteries. Based on this ultrasound-derived calculation, the degree of pulmonic stenosis is determined, and in turn it is then possible to know whether treatment is essential, or not required at all.

Treat Method: Since pulmonic stenosis is a narrowing of a region in the heart, the degree of concern depends directly on the degree of narrowing. Mild or moderate stenosis generally does not require any intervention at all. In some cases, additional findings on X-rays or cardiac ultrasound may justify starting daily medication, but with mild or moderate pulmonic stenosis, this is uncommon. With severe pulmonic stenosis, there is a strong likelihood of life-threatening problems at some point if treatment is not undertaken. Conversely, a good/normal quality of life and lifespan are expected with surgical treatment in the vast majority of cases. Surgery for pulmonic stenosis consists of enlarging the narrowed pulmonic valve so that circulation is improved and the strain on the heart is reduced. This is usually accomplished through minimally-invasive surgery: under general anesthesia, a catheter (long tube) is threaded through a blood vessel in the neck or groin and a balloon on it is inflated when it is positioned at the area of the pulmonic stenosis. The inflation of the balloon stretches the narrowed space in a way that tends to remain permanent, even after the balloon is deflated and the catheter removed. The long-term result is that the resistance to blood flow is lessened and the heart resumes a more normal degree of work. Some dogs are not candidates for this type of surgery: severe pulmonic stenosis may sometimes be inoperable. In these cases, treatment with beta-blocking drugs, which protect the heart against the damaging effects of adrenaline rushes, may be advocated by the veterinarian as a preventive measure. Dogs with mild pulmonic stenosis and most dogs with moderate pulmonic stenosis enjoy normal lives without treatment. Some dogs with moderate pulmonic stenosis and virtually all dogs with severe pulmonic stenosis have a shortened lifespan if it is left untreated. It is important to note that pulmonic stenosis does not cause pain, and it is not "wrong" or "unfair" to have a dog live with pulmonic stenosis of any degree of severity. The treatments described above are aimed at improving lifespan and quality of life in the future.

Breeder Advice: Affected individuals and their parents should not be used for breeding. Siblings should only be used after careful screening. If any affected offspring are born, breeding of the parents should be discontinued.

Disease Description Source: Link