First ablation
The cycle length of AT was 400-500 ms long or so. Activation mapping revealed a distal- to- proximal atrial activation sequence in coronary sinus. Further endocardial mapping demonstrated activation time of −112 msec and −105 msec (relative to the onset of the A wave at CS9-10) in the right ventricular outflow tract (RVOT) and LAA, respectively.
A TactiCath Quartz ablation catheter (St. Jude Medical, St. Paul, MN, USA) was used for ablation. Radiofrequency energy applications at multiple sites with early endocardial activation in RVOT did not terminate the tachycardia. Then the ablation catheter was placed at an early activation site of LAA, and multiple attempts using a temperature of 43°C and power settings of 17 to 25 W at this site did not terminate the AT either.