A grade 4/6 harsh ejection type (crescendo-decrescendo) systolic murmur (heard over the left heart base) caused by moderate subaortic stenosis (SAS) is auscultated in this patient.
A moderate to severe SAS murmur is typically harsh, of mixed frequency, and radiates toward the right heart base and up the neck along the carotid arteries. Pulse quality might be normal with moderate SAS, whereas it may be diminished with severe SAS. Left ventricular enlargement patterns may be less severe or absent on ECGs in a dog with moderate SAS (compared with severe SAS); this may be an additional way to distinguish or classify severity. Definitive diagnosis of SAS and severity require echocardiography.