Peri–coronary sinus atrial flutter associated with prior slow pathway ablation

Introduction A human anatomic study has shown that a cuff of striated muscle consistently surrounds the venous wall of the coronary sinus (CS) and is connected to the left atrium (LA) by muscular bundles in a variable fashion. The presence of electrical connections between the CS musculature and LA myocardium provides a potential anatomic substrate for reentry. In fact, atypical atrial flutter (AFL) involving the CS musculature in its reentrant circuits has been reported, and some studies have suggested that reentry via the CS–LA electrical connections could contribute to the initiation and maintenance of atrial fibrillation.