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.