Objectives: This study was conducted to estimate the incidence of aortic stenosis (AS) in a group of Boxers evaluated by auscultation, ECG, blood pressure measurement and Doppler-echocardiography.
Background: The Boxer is a breed at significantly increased risk of AS. The prevalence of murmurs and Doppler-echocardiographic findings consistent with AS in this breed is reportedly high.
Animals, materials and methods: Eighty-nine Boxers were evaluated by auscultation, and final murmur grade recorded after stress testing. Doppler echocardiography was performed in fifty-five adult Boxers. Electrocardiograms (ECG, n=53), non-invasive blood pressure measurement (n=32), and Holter monitoring (n=24) were performed in selected dogs. Degree of AS was based on the aortic peak flow velocity (Ao PFV). Final Ao PFV was recorded as the highest value obtained after stress testing. AS was defined as an Ao PFV>2m/s on continuous wave Doppler, using the subcostal window. Pressure gradients (Deltap) were calculated using the modified Bernoulli equation (Deltap=4V(2)). Mild AS was defined as Deltap=16-40mmHg, moderate AS Deltap=40-75mmHg, and severe AS Deltap>75mmHg.
Results: 62% of adult Boxers evaluated by echocardiography had an Ao PFV>2m/s suggestive of AS. Systolic basilar ejection murmurs were diagnosed in 73%. Murmur intensity showed a statistically significant correlation with Ao PFV (p<0.05). ECG abnormalities were only detected in dogs with severe AS.
Conclusion: The study reports on systolic murmurs and Doppler-echocardiographic findings consistent with AS, as well as ECG and blood pressure measurements in a sample of pure-breed Boxers.