Ebstein anomaly (EA) is a rare type congenital heart disease characterized by an apical displacement of the tricuspid valve leaflets in the right ventricle (RV), causing dilation of the right atrium (RA) and decrease in the functional RV size. Few studies have been dedicated to canine EA. The objective of this retrospective study was to characterize the epidemiological, clinical, and echocardiographic findings associated with canine EA, as well as survival.

The case records of dogs diagnosed with EA by use of echocardiography (2002–2017) were reviewed. The study population consisted of 40 dogs with EA (median age at diagnosis=15 months [IQR 7–36], male-to-female ratio=1.5). Only medium to large breeds were represented, the most common breed being Labrador Retriever (24/40, 60%). Eight dogs (20%) had a hemodynamically compromise concurrent heart disease (n=7) or respiratory disease (n=1), and were therefore excluded from subsequent analysis.

A right apical systolic heart murmur (median grade=5 [IQR 4–5]) was detected in all dogs, and 13/32 dogs (41%) presented clinical signs related to EA. Dilation of the RA was moderate to severe in most dogs (median RA to left atrium [LA] ratio=1.45 [IQR 1.29–1.72]). Several echocardiographic indices used in human pediatrics to evaluate EA were calculated, including the displacement index (distance from the hinge point of the anterior mitral leaflet to that of the delaminated septal leaflet divided by body surface area: median=17.4 mm/m² [IQR 12.0–21.9]) and the Celermajer index (ratio between the RA area and the sum of the areas of the RV, LA and left ventricle, median=1.0 [IQR 0.5–1.3]).

Follow-up was available for 25/32 dogs. Death of cardiac origin was reported in 4/25 dogs (16%) and all-cause death in 8/25 dogs (32%); median age at all-cause death was 73 months. Median time to all-cause death was 74 months after the diagnosis of EA. Median time to cardiac death (CD) could not be calculated, due to the high proportion of dogs still alive at the end of study. It is estimated that 72% dogs [95% CI, 50–86%] did not present CD 160 months after the diagnosis of EA. Univariate analyses showed that time from diagnosis to CD was associated with the presence of ascites, clinical signs, a RA:LA ratio ≥2, the presence of a right thrill, and a Celermajer index ≥1.

In conclusion, RA enlargement is significantly associated with decreased survival time of dogs with EA although most may live years and may not die from CD.

Disclosures

Disclosures to report.

C. Poissonnier: Fondation Un Coeur/Vetoquinol sponsoring for clinical projects unrelated to this study.