Screening for aortic stenosis in the Boxer: Auscultatory, ECG, blood pressure and Doppler echocardiographic findings

Abstract

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 > 2 m/s on continuous wave Doppler, using the subcostal window. Pressure gradients (Δ p) were calculated using the modified Bernoulli equation (Δ p = 4 V 2). Mild AS was defined as Δ p = 16–40 mmHg, moderate AS Δ p = 40–75mmHg, and severe AS Δp > 75mmHg. Results 62% of adult Boxers evaluated by echocardiography had an Ao PFV > 2 m/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.