Ablation of atrioventricular accessory pathways: current technique-state of the art

Local Atrial/Ventricular Ratio as an Adjuvant Marker for Catheter Ablation of Atrioventricular Accessory Pathways

Background and Objectives

The earliest atrial (A)/ventricular (V) activation potential, or accessory pathway (AP) potential are commonly used as ablation targets for atrioventricular (AV) APs. However, these targets are sometimes ambiguous.

Subjects and Methods

We reviewed 119 catheter ablation cases in 112 patients diagnosed with orthodromic atrioventricular reentrant tachycardia (AVRT) or Wolff-Parkinson-White (WPW) syndrome. Local A/V amplitude potentials with the earliest activation or AP potential were measured shortly before achieving antegrade AP conduction block, ventriculoatrial block during right ventricle (RV) pacing, or AVRT termination with no AP conduction.

Results

APs were located in the left lateral (55.5%), left posterior (17.6%), left posteroseptal (10.1%), midseptal (1.7%), right posteroseptal (7.6%), right posterior (1.7%), and right lateral (5.9%) regions. The mean earliest activation time was 16.7±15.5 ms, mean A/V potential was 1.1±0.9/1.0±0.9 mV, and mean A/V ratio was 1.7±2.0. There was no statistically significant difference between the activation methods (antegrade vs. RV pacing vs. orthodromic AVRT) or AP locations (left vs. right atrium). However, when the local A/V ratio was divided into 3 groups (≤0.6, 1.0±0.3, and ≥1.4), the antegrade approach resulted in an A/V ratio greater than 1.0±0.3 (86.7%, p=0.007), and the orthodromic AVRT state resulted in a ratio of less than 1.0±0.3 (87.5%, p<0.001).

Conclusion

The mean local A/V potential and ratio did not differ by activation method or AP location. However, a different A/V ratio based on activation method (≥1.0±0.3, antegrade approach; and ≤1.0±0.3, orthodromic AVRT state) could be a good adjuvant marker for targeting AV APs.

New access for radiofrequency catheter ablation of left-sided atrioventricular accessory pathways: safety and efficacy of the transradial approach

BACKGROUND

The safety and efficacy of the transradial approach for radiofrequency catheter ablation (RFCA) of left-sided atrioventricular accessory pathways (APs) was evaluated in the present study.

METHODS AND RESULTS

Included were 40 consecutive patients with type A Wolff-Parkinson-White (WPW) syndrome who underwent RFCA via the radial artery route, and 30 patients with type A WPW syndrome who underwent RFCA via the transfemoral approach (controls) were retrospectively chosen for control. All 45 APs in the 40 patients were successfully ablated: 35 APs were successfully blocked with 1 ablation attempt, and the other 10 APs were ablated after 2-4 attempts. Compared with the transfemoral approach, the total procedure time for the transradial approach was longer (40 +/- 7.7 vs 32.4 +/- 8.7 min, P<0.05) and the fluoroscopic time was similar (7.2 +/- 2.2 vs 7.9 +/- 3.9 min, P>0.05). There were no vascular complications in the transradial group, but 2 patients in the transfemoral developed local hematoma. There was no recurrence of arrhythmia in either group.

CONCLUSIONS

The transradial approach is a safe and effective access for RFCA of left-sided APs.