Occurrence of mitral valve insufficiency in clinically healthy Beagle dogs

Chronic degenerative valve disease (CDVD) is the most common cardiac disease in dogs, usually resulting in mitral valve insufficiency (MVI). The goal of this study was to investigate the occurrence of MVI in clinically healthy Beagle populations. A total of 79 adult healthy Beagles (41 females and 38 males; age: 5.6 ± 2.7 years, range 1.4 to 11.7 years) were examined. The diagnosis of MVI was based on the detection of a systolic murmur heard above the mitral valve, and was confirmed by colour flow Doppler (CFD) echocardiography. Systolic mitral valve murmurs were detected in 20/79 dogs (25.3%), of them 11 males and 9 females with no statistically significant gender difference (P = 0.6059). The strength of the murmur on the semi-quantitative 0/6 scale yielded intensity grade 1/6 in 10 dogs, grade 2/6 in 4 dogs, and grade 3/6 in 6 dogs. Mild to moderate MVI was detected by CFD in all these 20 dogs with systolic murmurs. Of them, 17 dogs had mild and 3 demonstrated moderate MVI, showing 10-30% and 30-50% regurgitant jets compared to the size of the left atrium, respectively. The age of dogs with MVI was 7.1 ± 2.3 years, which was significantly different from that of dogs without MVI (5.1 ± 2.7 years, P = 0.0029). No significant differences in body weight (P = 0.1724) were found between dogs with MVI (13.8 ± 2.8 kg) and those without MVI (12.8 ± 3.0 kg). Mitral valve disease causing MVI is relatively common in Beagle dogs, just like in other small breed dogs reported in the literature.