A atrial flutter consisted of two different conduction pathways.

The patient is a 64-year-old male who had been implanted with a DDD-pacemaker for sick sinus syndrome in 2003. In January 2006, he experienced palpitations and visited a local hospital on the second day of occurrence. After an electrocardiography (ECG) revealed atrial flutter (AFL) during palpitation, which was resistant to administered verapamil, the patient was admitted to our hospital for curative treatment. Electrophysiological study revealed a common AFL (AFL1) initiated by atrial burst pacing. We performed isthmus radiofrequency (RF) ablation against AFL1 successfully, after which another common AFL (AFL2) with differing atrial rate was detected. A second ablation operation with standard catheterization techniques was successful, suggesting that two pathways with differing conduction times existed.