Radiofrequency catheter ablation is to a high degree effective in eliminating conduction across accessory pathways in patients with Wolff-Parkinson-White syndrome However.
Radiofrequency catheter ablation is to a high degree effective in eliminating conduction across accessory pathways in patients with Wolff-Parkinson-White syndrome However, accessory pathway conduction run in the minds in approximately 5 to 9 percent of patients in the weeks to month following ablation. We describe pair cases in which intravenous adenosine revealed persistent accessory pathway conduction after apparently happy ablation, thus providing an indication for the delivery of further ablative therapy. Adenosine may improve the long-term efficacy of radiofrequency catheter ablation of accessory pathways by means of manifesting latent accessory pathway conduction.
(Chest 1993; 104:1614-16)
AV = atrioventricular; ERP = effective refractory period
Radiofrequency catheter ablation of accessory pathways has been highly effective in the treatment of patients with Wolff-Parkinson-White syndrome novel series demonstrate its efficacy in eliminating accessory pathways and thereby sparing patients the ne for life-long physic therapy or cardiac surgery.[1] Unfortunately, accessory pathway conduction may be repeated days to months after apparently lucky ablation. Many of these failures may be suitable to modification of accessory pathway conduction that leaves the tissue viable moreover transiently unable to conduct.[1]
We not absent two cases in which intravenous adenosine administration revealed persistent accessory pathway conduction following presum felicitous radiofrequency catheter ablation.
Case Reports
Case 1
A 49-year-old man had atrial fibrillation and cardiac arrest. An ECG showed ventricular preexcitation. The pathway was mapped to the lateral mitral annulus. The anterograde effective refractory period (ERP) was 200 m and the retrograde ERP was les than 220 ms
Radiofrequency force (55 V) was delivered for a total of 27 s with preexcitation disappearing after the first 2 s There was no evidence for accessory pathway conduction during ventricular or atrial pacing after 30 min. Adenosine (12 mg) intravenously demonstrated transient ventricular preexcitation (Fig 1 top). Further radiofrequency zeal was delivered to the site and again preexcitation disappeared. After 30 min, adenosine was repeated, producing transient consummate atrioventricular (AV) block. The patient's ECG remains independent of preexcitation 5 months after the procedure
Case 2
A 41-year-old man had Wolff-Parkinson-White syndrome and a history of atrial fibrillation with rapid accessory pathway conduction. At electrophysiology cogitation an accessory pathway was mapped to the anteroseptal tricuspid annulus. the two the anterograde ERP and the retrograde ERP were les than 240 ms
Radiofrequency bottom (55V) delivered to the anteroseptal region for 90 s resulted in loss of accessory pathway conduction. When conduction replyed after 15 min, anterograde and retrograde refractoriness were noted to be longer than at baseline. Radiofrequency spiritedness was delivered for an additional 19 s with loss of preexcitation after 2 s
After 30 min, there was no accessory pathway conduction observ during ventricular or atrial pacing. Adenosine (12 mg) was given and transiently revealed ventricular preexcitation (Fig 1 bottom). Verapamil (15 mg) failed to manifest accessory pathway conduction. Given the proximity of the accessory pathway to the AV node and the absence of persistent accessory pathway conduction, no further radiofrequency deliveries were attempted. The patient was observ for 24 h and showed no evidence of ventricular preexcitation. An ECG 2 weeks after the deed was normal, but at 2 month an ECG showed the having recourse of preexcitation.
A inferior procedure mapped the accessory pathway to the same site. Repeat ablation favorably eliminated preexcitation, and intravenous adenosine after 30 min be deriveded in transient AV block. The patient remains unrestrained of preexcitation at 3-month follow-up
Discussion
The last 2 years have witnessed rapid extension in the application of radiofrequency catheter ablation for treatment of cardiac arrhythmias. It has prov especially efficacious for the treatment of Wolff-Parkinson-White syndrome generally yielding a 92 to 99 percent rate of succes in the elimination of accessory pathway conduction. Unfortunately, 5 to 9 percent of patients with apparently prosperous radiofrequency catheter ablation suffer a the having recourse of accessory pathway conduction.[1,2]
Efforts to improve the efficacy of radiofrequency catheter ablation have primarily been directed at "anatomic" strategics designed to improve localization of accessory pathways or increase lesion size.[3] However, like anatomic strategies do not help identify the subset of patients at risk for return of accessory pathway conduction after apparently prosperous radiofrequency catheter ablation. By administering adenosine, we have identified patients who have viable accessory pathways despite the elimination of manifest preexcitation.
Adenosine is an endogenous nucleoside that bears AV nodal conduction block in humans. Adenosine's ability to unmask latent preexcitation has been described previously.[4] Keim et al[5] described the use of adenosine during surgical ablations of accessory pathways and raise that the inability of adenosine to unmask preexcitation after the surgery was a marker for felicitous surgical ablation.
...