METHODS
Consecutive patients undergoing CTI ablation in the absence of any other ablation target received a bolus injection of adenosine 10mg via a femoral venous access sheath at 5 minutes after the apparent achievement of persistent bidirectional CTI block. All patients were treated by the same operators in 2 centres. All procedures were performed under local anaesthesia using right femoral venous access and using fluoroscopic guidance to place a deflectable diagnostic catheter in the coronary sinus and a multipolar catheter in the lateral right atrium. A Blazer large-curve 8mm or 10mm tip ablation catheter was used to create a line of lesions to block the CTI and to perform consolidating lesions to create a clear zone of abolition of local electrograms.
After achievement of satisfactory CTI block, a waiting period was commenced. At 5 minutes into the waiting period, intravenous adenosine 10mg was administered centrally. The patient observations were monitored, the surface electrocardiogram and intra-cardiac electrograms were assessed for both evidence of adenosine-induced AV block and for transient re-conduction of the CTI. Further RF ablation was performed for all those who had persistent CTI conduction recurrence. For all those who required re-ablation to achieve enduring CTI line block, a full waiting period was respected, with no re-testing with adenosine.