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Transient complete heart block during radiofrequency ablation of a left lateral bypass tract
N J Stamato1, S L Eddy, D J Whiting
1Cardiac Electrophysiology Laboratory, Wilson Memorial Regional Medical Center, United Health Services Hospitals Inc., Johnson City, New York 13790-2143, USA.
Insights
Radiofrequency catheter ablation effectively treats Wolff-Parkinson-White syndrome. For left free-wall bypass tracts, a single catheter technique is used, with temporary pacing recommended if right bundle branch block is present.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Devices
Background:
- Radiofrequency (RF) catheter ablation is a standard treatment for accessory bypass tracts causing Wolff-Parkinson-White (WPW) syndrome.
- A single catheter technique is feasible for left ventricular free-wall bypass tracts.
Observation:
- A case of WPW with rapid atrial fibrillation is presented, treated with single catheter ablation of a left free-wall bypass tract.
- During ablation, transient complete atrioventricular (AV) block occurred, likely due to proximity to the His-Purkinje system.
- The patient had baseline pre-excitation and right bundle branch block (RBBB) on ECG.
Findings:
- Successful ablation of the accessory pathway was achieved using the single catheter technique.
- AV conduction resumed with a persistent RBBB pattern post-ablation.
- A temporary right ventricular pacemaker was placed, facilitating successful ablation.
Implications:
- The single catheter technique is effective for left free-wall accessory pathways in WPW syndrome.
- Transient AV block is a potential complication, especially in patients with pre-existing RBBB.
- Prophylactic temporary pacing is advised for left-sided ablations in patients with ECG findings suggestive of RBBB.
Abstract:
RF catheter ablation of accessory bypass tracts associated with the Wolff-Parkinson-White syndrome has become an accepted and widespread therapy. When bypass tracts are located in the free wall of the left ventricle, a single catheter technique may be utilized. A single catheter is placed via the femoral artery, across the aortic valve into the left ventricle. Mapping is performed during sinus rhythm, and ablation performed at the site of recording of Kent bundle activation. We describe a case of a patient with Wolff-Parkinson-White syndrome presenting with rapid atrial fibrillation requiring cardioversion. This patient subsequently underwent catheter ablation of a left free-wall bypass tract using the single catheter technique. At baseline, preexcitation and right bundle branch block (RBBB) were present on the ECG. During catheter ablation of the accessory pathway, transient complete AV block was seen. This was felt likely to be due to trauma to the His bundle, or more likely to the left bundle branch, as the ablation catheter crossed the aortic valve. The bypass tract was successfully ablated after placement of a temporary right ventricular pacemaker. AV conduction resumed with a pattern of RBBB. A temporary right ventricular pacing catheter should be placed prior to RF ablation of left-sided bypass tracts when the ECG is also suggestive of RBBB.