Abstract Body: Cor Triatrium Dexter (CTD) is a very rare congenital heart defect, accounting for less than 0.004% of congenital heart malformations, in which a persistent embryonic right sinus valve divides the right atrium into two chambers. Cor triatriatum is most commonly present in childhood, and diagnosis in adulthood is rare. When the septation is mild, the condition is often asymptomatic, and is found incidentally during surgery to correct other cardiac abnormalities or during echocardiography.
64-year-old man with a history of atrial fibrillation (on apixaban), type 2 diabetes, hypertension, COPD (on 2 L home oxygen), and ESRD on MWF dialysis presented with acute-on-chronic shortness of breath and was admitted for CHF exacerbation; TTE revealed Cor Triatriatum Dexter with significant right heart enlargement and dysfunction, severe tricuspid regurgitation, a small right-to-left shunt, and preserved LV systolic function (EF 55–60%).
Cor triatriatum dexter results from persistence of the embryonic right sinus valve, creating a membrane that divides the right atrium into two chambers. Mild septation is often asymptomatic and incidentally identified, whereas more significant septation can obstruct right-sided inflow or outflow, leading to elevated venous pressures and right-sided heart failure, as seen in our patient who presented with congestive heart failure symptoms and was subsequently found to have CTD. Diagnosis is most commonly established by echocardiography.
Historically, surgical membrane resection has been the definitive treatment for symptomatic obstruction; however, asymptomatic patients generally require no intervention, and symptomatic cases may be managed with diuretics, fluid and salt restriction, arrhythmia rate control, and inotropic support when indicated. Our patient was treated conservatively with diuretics and fluid and salt restriction.
In conclusion, this case highlights cor triatriatum dexter as an underlying anatomic substrate for right-sided heart failure. The patient’s presentation underscores how congenital atrial septation can contribute to chronic right heart remodeling, valvular dysfunction, and venous congestion, emphasizing the importance of echocardiography in identifying structural congenital causes of heart failure even later in life.