Transvenous radiofrequency catheter ablation of atrioventricular accessory pathways.

Transvenous delivery of radiofrequency energy is an attractive new technique in nonsurgical treatment of cardiac arrhythmias. We used radiofrequency catheter ablation in two patients with tachycardias complicating the Wolff-Parkinson-White syndrome. The first patient was a 28-year-old male who had suffered cardiac arrest from rapid preexcited atrial fibrillation (shortest RR interval of 180 ms) due to a left anterolateral free wall accessory pathway. The accessory pathway was mapped by means of positioning a 7F quadripolar catheter with a 4 mm tip to obtain the shortest atrial to ventricular timing during preexcited sinus rhythm. Unmodulated radiofrequency energy (750 KHz) was applied unipolarly between the distal pole of the catheter against an indifferent plate at the back. Using an applied energy of 30W, this resulted in the disappearance of both anterograde and retrograde conduction. The second patient was a 26-year-old man with concealed left posterolateral pathway. This was ablated at the site which corresponded to the shortest ventriculatrial timing during sustained atrioventricular reciprocating tachycardia. There was no complication from this procedure and both patients were discharged on the fourth day after the procedure and returned to work soon afterwards. Radiofrequency ablation is a safe and effective means for the treatment of paroxysmal supraventricular tachycardias.