Radiofrequency (RF) ablation of the His bundle was attempted in 30 consecutive patients with atrial flutter or fibrillation. A 7 French quadripolar catheter with a 4-mm distal electrode was advanced from the right femoral vein (21 patients), or subclavian vein (two patients) and positioned across the tricuspid valve. Adequate His-bundle potentials were obtained in all patients. However, in six patients atrioventricular (AV) block could not be obtained after multiple (mean = 8) applications of RF energy from the conventional right-sided approach. In these patients the same catheter was advanced to record a His potential through a retrograde arterial approach. AV block was created in all patients with one to three applications of RF energy. The duration of the procedure was 22 to 90 minutes for the right-sided approach and 5 to 10 for the left-sided approach (P < 0.005). Subsequently, in seven patients a left-sided approach was used first. One to six applications of RF energy were required to create AV block. The radiation exposure time was 3 to 20 minutes. No complications occurred.
Conclusions: RF ablation of the His bundle seems easier using a left-sided than a right-sided approach, reduces procedure and radiation time, and avoids recovery of conduction. These data suggest that a left-sided approach, in spite of requiring arterial catheterization, may be preferable to a right-sided approach.