A combination of a grade 4/6 harsh ejection type (crescendo) systolic murmur and a soft grade 2/6 diastolic decrescendo murmur (over the left heart base) caused by severe subaortic stenosis and mild aortic insufficiency in a dog is appreciated in this heart sound.
The murmur of valvular and subvalvular aortic stenosis is a systolic ejection (crescendo-decrescendo) murmur best heard at the left heart base. A moderate to severe subvalvular aortic stenosis murmur is usually harsh and of mixed frequency; it often radiates towards the right heart base and up the neck along the carotid arteries.