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[Retrograde conduction (ventriculo-atrial) in patients with AV or intraventricular block. Electrophysiologic
J Kaźmierczak1, Z Kornacewicz-Jach, R Gil
1Klinika Kardiologii Pomorskiej AM, Szczecinie.
Insights
Ventriculoatrial conduction was evaluated in patients with complete AV block and bifascicular block. Higher prevalence of ventriculoatrial conduction was observed in bifascicular block patients, suggesting complex properties influencing pacing decisions.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Device Technology
Abstract:
The purpose of the study was to evaluate ventriculoatrial conduction in patients with chronic complete AV block (AVB) (35 pts--gr. A), who were qualified for pacemaker implantation and in patients with bifascicular block (BFB) (20 pts--gr. B), who had electrophysiological study performed to determine indications for permanent pacing. Anterograde and retrograde conduction by accessory pathways were excluded in all patients. Incremental ventricular pacing (60-80 bpm to 200-220 bpm) and programmed ventricular stimulation were performed. Ventriculoatrial (VA) conduction was present in 12 of 35 patients in gr. A (34%) and in 15/20 patients in gr. B (75%). Mean VA conduction time was 192 +/- 50 ms in gr. A and 200 +/- 54 ms in gr. B, effective refractory period of right ventricle (ERP-RV) was 270 +/- 30 ms and 250 +/- 29 ms respectively. Mean retrograde Wenckebach point was 128 +/- 41 bpm in gr. A and 132 +/- 30 bpm in gr. B. The level of VA Wenckebach block in gr. A was found at AVN in 4 of 12 patients and in remaining was not directly recognised. Levels in gr. B were: AVN--6, not recognised--9 patients. Ventriculoatrial conduction shows complex properties and dependence on the type of ventricular stimulation. Electrophysiological study enables to find a level of retrograde block in some patients.