Epidemiological and Morphological Studies of Double-Chambered Right Ventricle in Dogs

Abstract

The double-chambered right ventricle (DCRV) is a rare congenital cardiac disease in dogs, and its detailed epidemiological and morphological features are not clearly understood. By investigating the profile, clinical signs, and characteristics of examination findings of eleven dogs with DCRV by means of a retrospective study, we attempted to clarify the epidemiology and morphology of the condition. The study group consisted of nine males and two females. Breeds included Pug (n=3), Miniature Dachshund (n=1), French Bull-dog (n=1), Shiba (n=1), and Retrievers (n=5). The attachment site of the anomalous muscular bundle was continuous with the cardiac apex in nine dogs, and it was attached to the right ventricle free wall in the other two dogs. In dogs with DCRV, at least one of the following conditions was present concurrently: congenital or acquired tricuspid valve regurgitation (TR), ventricular septal defect, and atrial septal defect. Also, the pressure difference between the two chambers increased over time, and progressive right-sided heart failure was observed. In summary, DCRV occurs in small breeds of dog as well as in large breeds of dog and it may be more prevalent in males. The existence of two types of DCRV in dogs was established. Dog with DCRVs will have a high incidence of concurrent cardiac abnormalities. Concurrent TR may be either congenital or acquired. DCRV is a congenital disorder, but the clinical condition progresses as the dog develops.

Echocardiography

“…388,390,396,[398][399][400][401][402][403] Abnormalities observed by 2D imaging include valvular thickening (dysplasia), fusion along the commissural edges, and varying degrees of annular hypoplasia. There is some controversy among cardiologists about the criteria for the diagnosis of subvalvular or infundibular pulmonary stenosis 400 versus double chambered right ventricle, 371,[404][405][406][407][408][409] especially in cats (Figure 8-49, C; . There is some controversy among cardiologists about the criteria for the diagnosis of subvalvular or infundibular pulmonary stenosis 400 versus double chambered right ventricle, 371,[404][405][406][407][408][409] especially in cats (Figure 8-49, C; .…”

“…This is an ostium primum ASD. 371,[404][405][406][407][408][409]520 Doppler imaging both verifies the shunt and helps to assess the severity of the lesion. The valve is incompetent (right panel) and in real time studies the regurgitant jet started in the LV and crossed the ASD to enter both atria.…”

Congenital Cardiopathies

“…In this malformation, the right ventricular cavity is divided into two parts by an abnormal muscular, fibromuscular, or fibrous band, sometimes with thick endocardial proliferation on its rim. The right ventricular cavity thus becomes divided into a proximal "high-pressure" chamber and distal "lowpressure" chamber [41,42]. The location of this band may vary but is usually downstream of the tricuspid septal leaflet, connecting the ventricular septum to the anterior wall of the right ventricle ( Figure 19-13) [43].…”

Combined double chambered right ventricle, tricuspid valve dysplasia, ventricular septal defect, and subaortic stenosis in a dog

“…This condition has been described in dogs, human beings [ 3 – 5 ], cats [ 6 ], and alpacas [ 7 ]. The dog breeds most frequently affected by this anomaly are large, such as Golden Retriever [ 2 , 8 ] and Boxer [ 9 ]. A case of DCRV was also reported in a Pug [ 10 ].…”

“…A case of DCRV was also reported in a Pug [ 10 ]. One study reported no sex predisposition [ 10 ] and another suggested that males were overrepresented [ 8 ]. There are two types of DCRV reported in human beings: a low (oblique) type [ 11 ] and a high (horizontal) type [ 5 , 11 ].…”