Radio Frequency Ablation                                                                   

Catheter ablation of an accessory pathway was undertaken in 1968 using an electrical current. This technique, whilst successful, was destructive and there were concerns regarding damage to adjacent structures. Accordingly the use of radiofrequency was developed to give a more targeted approach and was first used in in 1986 (Borggrefe M et al. J Am Coll Cardiol 1987;10:576).

Technique

The initial step is an electrophysiology (EP) study applying frequent premature stimulations through the catheter placed at various sites in the heart to induce the arrhythmia. Once the mechanism has been identified and the best site to interrupt the accessory pathway determined a radiofrequency (300 to 1000 kHz) burst is applied through the catheter tip. The RF energy heats the tissues and renders a small area (2 - 4 mm³) electrically inert. The size of the lesion is dependent upon contact of the catheter with the myocardium, the energy used and the length of the burst. The EP study is then repeated to confirm that the pathway has been ablated. Initially these studies took several hours but now the procedure time for straightforward pathways may be less than 1 hour.

Complications

The risk of heart block is less than 1% even for ablating the pathway in AV node reentrant tachycardia. The remaining risks are also less than 1% and relate to that of any cardiac catheterisation procedure.

Results

The results are best for AV reentrant tachycardia and AV node reentrant tachycardia with success rates for experienced centres around 98%. There is a small risk of recurrence. Success rates for flutter and and fibrillation are significantly lower.

This page was last edited 14/2/2004