Radiofrequency catheter ablation of posterior paraseptal accessory pathway with atresia of the coronary sinus ostium.

A 42-year-old man was referred to our hospital for an electrophysiologic study because of recurrent episodes of palpitation. On coronary angiogram, an anomalous atresia of the coronary sinus (CS) ostium was discovered. The ablation catheter was inserted from the right femoral artery to the accessory pathway (AP) of posterior paraseptal area. The earliest retrograde atrial activation was recorded in the 5-6 o'clock region of the mitral annulus. Radiofrequency energy was delivered to this site, resulting in elimination of the AP. After this application, there was persistent ventriculoatrial dissociation and led to successful ablation of the AP.