Pathology of a lesion ablated from inside the coronary sinus

摘要

A 64-year-old woman with a history of a healed an-teroseptal myocardial infarction underwent radiofrequency (RF) catheter ablation of paroxysmal supraventricular tachycardia refractory to drug therapy. Transthoracic echocardio-graphy revealed the presence of a 16% left ventricular (LV) ejection fraction. Electrophysiologic studies were performed with standard catheters placed in the high right atrium, His-bundle region, and at the right ventricular (RV) apex, and a 20-pole catheter with 5-mm interelectrode spacing placed in the coronary sinus (CS). The earliest site of atrial activation during RV apical pacing was observed in the distal CS, without decremental conduction, (Fig. 1A), consistent with ventriculoatrial conduction over a left posterolateral accessory pathway (AP).