Case Description: Cor Triatriatum Dexter and Tricuspid Valve Stenosis in an 8 month old Labrador retriever with signs of right sided congestive heart failure. Clinical Findings: History of lethargy and inappetence which progressed to several episodes of acute collapse. Physical examination showed severe ascites, tachycardia with bilaterally muffled heart sounds (right worse than left), tachypnea, cachexia, weak pulses. Echocardiography and angiography revealed severe tricuspid valve stenosis, cor triatriatum dexter, Ebstein's anomaly, small right ventricular chamber, and tricuspid/pulmonic/mitral valvular regurgitation.
Treatment and Outcome: Abdominocentesis was performed upon presentation, and oral furosemide and enalapril were administered. Pericardiocentesis was performed once or twice daily as needed. Balloon valvuloplasty of the tricuspid valve stenosis resulted in an improved hemodynamic gradient, but pericardial fluid had reaccumulated after the procedure. Repeat balloon valvuloplasty and pericardial window were recommended, but the owners opted for humane euthanasia. Clinical Relevance: Cor triatriatum dexter and/or tricuspid valve stenosis should be considered as a differential diagnosis in all cases of young dogs with signs of right sided congestive heart failure.