Hyperacute Iatrogenic Atrial Septal Defect Expansion Driven by Tricuspid Regurgitation Jet Impingement.

BACKGROUND

Iatrogenic atrial septal defects (iASDs) after mitral transcatheter edge-to-edge repair (M-TEER) are generally benign. However, advanced atrial remodeling can trigger catastrophic mechanical failure via rapid morphologic expansion.

CASE SUMMARY: An 84-year-old woman with atrial fibrillation and diastolic dysfunction underwent M-TEER. Despite a stable intraprocedural iASD, she developed cardiogenic shock within 3 hours. Three-dimensional transesophageal echocardiography documented hyperacute doubling of the defect area. The mechanism was direct tricuspid regurgitation (TR)-jet impingement on the thinned septum, reflecting severely impaired left atrial compliance. Emergency iASD closure using "stationary deployment" prevented further traumatic tearing, resulting in immediate hemodynamic stabilization.

DISCUSSION: This case identifies TR-jet impingement as a predictor of acute iASD expansion. Transesophageal echocardiography is essential for monitoring this mechanical vicious cycle.

TAKE-HOME MESSAGES: Impaired atrial compliance and TR-jet impingement can cause rapid iASD enlargement after M-TEER. Prompt recognition and closure are vital for managing this life-threatening complication.