The Hidden Burden of Iatrogenic Atrial Shunting in Severe Tricuspid Regurgitation: A Case Report

Background: Iatrogenic atrial septal defects (iASDs) following transseptal puncture are usually benign. However, in the presence of severe tricuspid regurgitation (TR), even small defects may become hemodynamically significant, leading to hypoxemia and worsening right heart failure. Aims: To describe the clinical and hemodynamic consequences of a persistent iASD after heterotopic caval valve implantation in a patient with severe TR and the outcome of percutaneous ASD closure. Methods and results: We present the case of an 82-year-old woman with severe TR and a persistent iASD following atrial fibrillation ablation, who developed progressive exertional desaturation evolving into resting hypoxemia. Because of prohibitive surgical and transcatheter risk for tricuspid valve repair or replacement, a heterotopic caval valve implantation was performed as a palliative strategy to reduce systemic congestion. Although the procedure was technically successful, hypoxemia worsened due to increased right-to-left shunting. Percutaneous ASD closure resulted in immediate normalization of systemic oxygenation and substantial improvement in symptoms and exercise capacity. Conclusions: Heterotopic caval valve may increase right atrial pressure and unmask or exacerbate right-to-left shunting in patients with pre-existing interatrial defects. Comprehensive hemodynamic evaluation and a tailored, stepwise management strategy are essential.