Incomplete Atrioventricular Canal Complicated by Cardiac Tamponade and Bidirectional Shunting in an Adult Dog

Abstract

An incomplete atrioventricular (AV) canal with bidirectional shunting and cardiac tamponade in a 6-year-old dog was initially diagnosed echocardiographically as a common atrium. The dog failed to respond to medical therapy and was euthanized. Upon necropsy, the defect was confirmed as an incomplete AV canal. A mechanism for the potential sequence of clinical events demonstrated in this dog is proposed.

A case of a complete atrioventricular canal defect in a ferret

“…Additionally, abnormalities of the tricuspid valve similar as to what observed in the presented case were observed in cats, where a large leaflet of the valve was more prominent [7]. Dogs were reported mainly with incomplete AVCD and, strikingly, in much lesser proportion than cats [2][3][4][10][11][12][13][14]. In horses, only complete AVCD cases were described [15][16][17][18].…”

“…A diagnosis of AVCD is performed based on cardiovascular examination using imaging methods like radiography, ECG, and echocardiography. Generally, radiography reveals cardiomegaly, especially regarding the right atrium, both ventricles, and a pronounced pulmonary artery [4,14]. The ECG commonly shows QRS changes compatible with conduction abnormalities, especially bundle branch blocks [3].…”

“…In veterinary medicine, AVCD has been described in several species: eight pigs [5], 31 cats [1,[6][7][8][9], nine dogs [2][3][4][10][11][12][13][14], and four horses [15][16][17][18]. Factors like oxygen deficiency, viral infection during early pregnancy, nutritional, genetic, and teratogenic factors have been suggested as possible factors triggering the development of this condition and possibly other congenital heart diseases [14,18]. To the author's knowledge, this is the first case of an incomplete AV canal in a ferret that has survived six months after the diagnosis with conservative therapy.…”

Congenital Cardiopathies

“…Endocardial cushion defects have been reported in both cats and dogs [126,[134][135][136], without any apparent breed or sex predisposition. In our experience, this disease is more frequently seen in cats than in dogs.…”

“…The predominant echocardiographic features of complete endocardial cushion defect include absence of atrioventricular septum and valvular malformation, a cleft anterior mitral leaflet, or a common atrioventricular valve [135]. The presence of a single common atrioventricular valve is well documented using the left parasternal apical 4 chambers and oblique views (Figure 19-62).…”