Note for Pet Owners:

This information is provided by Provet for educational purposes only.

You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Because aortic stenosis is thought to have a genetic basis affected animals should not be bred from.

Topics on this Page:


Narrowing of the outflow channel between the left ventricle and the main artery of the body, the aorta, is called aortic stenosis.

The narrowing can occur at three sites :

At the level of the aortic valve (valvular)

"Above" the aortic valve , in the aorta (supravalvular) - rare (has been caused by vitamin D supplementation in pregnant bitches)

"Below" the aortic valve, in the ventricle (subvalvular) - most common (90% of cases)

The cause is believed to be a genetically inherited defect

Breed Occurrence

There is reported to be an increased risk of developing aortic stenosis in Boxers (50% of cases reported in the UK), English Bull Terriers, German Shepherd Dogs, German Short-haired Pointers, Golden Retrievers, Newfoundlands and Samoyeds It has also been seen in smaller breeds such as terriers.

Aortic stenosis is uncommon in cats.

Signs of aortic stenosis can vary from no signs at all to sudden death. In most cases an abnormal heart sound ( a systolic murmur) on auscultation of the heart is the only finding. This sound is loudest on the left side of the chest at the level of the heart base. Some dogs with aortic stenosis may show signs of exercise intolerance or feinting/syncope

If cardiac output is significantly impaired left-sided heart failure can result - but this is not common..


X-rays - often no abnormality is seen. May see a "bulge" in the aorta on the dorsoventral view.

ECG - Often no evidence of left ventricular enlargement. Severely affected animals develop ventricular tachydysrhythmias.

Echocardiography - can be useful in severe cases, but Doppler echocardiography is the best method to identify the lesion -because  there is an obvious increase in the velocity of blood flow as it passes through the narrowed area of stenosis.

Catheterisation and angiography - a direct left ventricular angiogram is best, but lesions will show up with non-selective angiography.


Most cases do not require treatment.

Usually treatment is aimed at improving cardiac output and controlling abnormal heart rhythms (dysrhythmias). b -blockers (e.g. propranolol at a dose rate of 0.25-0.5mg/kg tid) or calcium channel blockers (e.g. diltiazem) have been used successfully. Procainamide has been used to control ventricular dysrhythmias

Dilatation of the stenosis using balloon catheters has not yet proved successful.

A fairly accurate prognosis can be given if the pressure gradient across the stenosis is measured (either by Doppler or direct catheterisation). If the pressure difference is greater than 100mm Hg and the animal has a grade 5/6 murmur the prognosis is guarded with a life expectancy of only 3-4 years. Less than 50mmHg with a murmur grade 2/6 suggests the condition is mild and a normal life expectancy can be given.

Long term problems

Updated January 2016