Prevalence of congenital heart disease in boxers in Italy

To evaluate the prevalence of congenital heart disease in boxers in Italy by auscultation and echocardiography.

This randomized study involved 500 boxers. The inclusion criteria were that the animals should be asymptomatic, older than 1 year and with a pedigree. Dogs with a heart murmur underwent a complete echo-Doppler examination. The criteria for the diagnosis of aortic or pulmonic stenosis were: heart murmur on cardiac auscultation; direct imaging of the obstructive lesions; turbulent aortic or pulmonic flow with peak velocity of >2 m/sec and > 1.5 m/sec, respectively.

265 out of 500 dogs exhibited a heart murmur on cardiac auscultation. According to echo-Doppler examination, 89 (17.8%) dogs were affected with congenital heart disease. Subaortic stenosis and/or pulmonic stenosis accounted for all cases identified, although subaortic stenosis was more prevalent. Type I (63.75%) and Type II (21.25%) subaortic stenosis were the most common forms of the disease. Type A was the most prevalent type of pulmonic stenosis (74.2%). None of the dogs with a heart murmur of grade 1/6 or 2/6 complied with all the pre-selected criteria, and they were not considered to be affected with congenital heart disease.

The prevalence of congenital heart disease in boxers in Italy appears to be very high (17.8%). In this study, subaortic stenosis and pulmonic stenosis accounted for all identified heart diseases. These findings support a the suspicion of these diseases when a heart murmur is found in a boxer, but only Doppler echocardiography can differentiate between subaortic stenosis and pulmonic stenosis.