A seven-week-old intact male German Shorthaired Pointer-cross, weighing 3.3 kg with a history of poor body condition, anorexia, reluctance to move and dyspnea, was presented to the Cardiology Clinic of the University of Agricultural Science and Veterinary Medicine, Cluj-Napoca, for further evaluation. On presentation, the dog was moderately dyspneic and lethargic, with a body condition score of 3/9 and tachycardia (230 bpm). A grade IV/VI right basilar systolic and a grade III/VI left basilar systolic heart murmur was present. Electrocardiographic findings included a sinus tachycardia with a heart rate of 230 bpm, P pulmonale (0.5 mV, Lead-II) and a normal mean electrical axis of the ventricular depolarization process. Standard transthoracic two-dimensional and Doppler echocardiography was performed in right and left lateral recumbencies using a 10 MHz, phased array transducer, according to ACVIM recommendations []. In the right-parasternal, long-axis, four-chamber view, a congenital TVD was identified with severe right atrial enlargement. The tricuspid valve annulus was displaced ventro-caudal, towards the right ventricular (RV) apex. A voluminously appearing tricuspid insufficiency jet with a 4.69 m/s peak flow velocity, along with mild mitral regurgitation was present. A severe, type B pulmonic stenosis [] with valvular dysplasia, severe thickening of the valve cusps and a hypoplastic valve annulus was also demonstrated. The peak flow velocity across the stenosis was 5.16 m/s. There was moderate to severe post-stenotic pulmonary arterial dilatation. There was generalized concentric RV hypertrophy, presumably, secondary to the severe PS. Aortic flow was laminar and its velocity was normal at 1.29 m/s. Due to the severe cardiac pathology, the dog was humanely euthanized with the owner’s consent and necropsy was allowed. For euthanasia we used T-61®, which was intravenous administered (0.5 ml/kg). Before euthanasia, the dog was anesthetized with a combination of xylazine (1 mg/kg, i.v.) and ketamine (10 mg/kg, i.v.). Necropsy revealed moderate hepatomegaly with diffuse hepatic steatosis. Within the gastrointestinal tract, multifocal ulcerative gastritis was present. Gross examination of the heart revealed marked right-atrial dilatation with TVD, consisting of marked hypoplasia of the chordae tendineae, tricuspid valve leaflet thickening, deformation and malposition. A large, ovoid, accessory orifice with smooth margins (measuring 0.9 cm) of the tricuspid valve was present. The accessory orifice corresponded to the third type of double-orifice tricuspid valve (DOTV), which is an extremely rare form of tricuspid anomaly in humans [–]. The DOTV involved the septal leaflet and it had its own subvalvular apparatus. Pulmonary valve stenosis and dysplasia with post-stenotic dilatation of the pulmonary trunk were confirmed. Within the ventricles, multiple recesses and elaborate trabeculation were projecting through both the apical and middle ventricular areas, with the LV being more severely affected. The non-compacted layer was mainly on the free walls, but also partially extending into the interventricular septum, in both the middle and the apical regions. The entire heart was fixed in 10% neutral buffered formalin, trimmed in a transversal plane, and multiple samples were routinely embedded in paraffin, sectioned, and finally stained with hematoxylin and eosin. Microscopically, the recesses appeared between multiple papillary trabeculae with a broad basis, communicating with the LV cavity. There were no elements identified to support the communication between the recesses and the coronary arteries. The entire LV cardiac wall thickness, including the noncompacted and compacted areas of both the free and the interventricular septal walls, was measured perpendicularly from the endocardial surface to the epicardium. The ratio between non-compacted and compacted areas was more than 50%. The same measurements were conducted on the RV myocardium, the ratio of which was even higher at 75%. Other histopathological findings were represented by diffuse subendocardial fibrosis and multifocal dystrophic mineralization of the left ventricle myocardium. These findings are consistent with the diagnosis of LVNC [, ] and include RV noncompaction involvement [].