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 :
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.
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.
Long term problems
Updated January 2016