# Successfully repaired adult cor triatriatum with mitral regurgitation and atrial fibrillation: a case report

## TL;DR

A 49-year-old woman with a rare heart defect, cor triatriatum, was successfully treated with surgery that resolved her mitral valve issue and atrial fibrillation.

## Contribution

The study demonstrates the effectiveness of combining mitral valve repair, the maze procedure, and resection of the anomalous septum in treating cor triatriatum in adults.

## Key findings

- Mitral regurgitation was well-controlled and atrial fibrillation resolved after surgery.
- Sinus rhythm was maintained for six months post-surgery with no recurrence of mitral regurgitation.
- Resolving membrane attachments was crucial for preventing macro-reentrant atrial tachycardia.

## Abstract

Rarely seen in adults, cor triatriatum is a congenital defect in which a membrane creates three atrial chambers in the heart. Atrial fibrillation (AF) is the most common complication, but repair procedures in adults remain unestablished.

A 49-year-old woman had cor triatriatum sinister (Lucas-Schmidt classification type I-A) with moderate mitral regurgitation and atrial fibrillation. Communication between the accessory chamber and the main chamber was established via a 10-mm fenestration with a pressure gradient of 14 mmHg. Mitral valve repair and the maze procedure, via radiofrequency ablation, was done after complete resection of the anomalous septum in the left atrium. Mitral regurgitation was well-controlled and atrial fibrillation disappeared. Sinus rhythm has been continually maintained at 6 months post-surgery, with no mitral regurgitation recurrence.

Here, a rare adult cor triatriatum case with simultaneous mitral valve regurgitation and atrial fibrillation was treated with good results. The maze procedure shows effectiveness for atrial fibrillation associated with cor triatriatum. Especially the anomalous membrane attachments must be resolved in addition to the conventional maze procedure because electrical mapping of Cor triatriatum sinister showed low-voltage zones at the membrane attachments and it cause macro-reentrant atrial tachycardia.