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Time relation between a syncopal event and documentation of atrioventricular block in patients with bifascicular

Fariborz Tabrizi1, Mårten Rosenqvist, Lennart Bergfeldt

  • 1Department of Cardiology, Karolinska Institute, South Hospital, Stockholm, Sweden. fariborz.tabrizi@karolinska.se

Cardiology
|October 10, 2006
PubMed

Insights

Syncope in bifascicular block (BFB) patients often signals future high-degree atrioventricular (AV) block. A bradycardia-detecting pacemaker can confirm this risk, justifying early pacemaker implantation.

Area of Science:

  • Cardiology
  • Electrophysiology
  • Medical Devices

Background:

  • Transient high-degree atrioventricular (AV) block is a frequent cause of syncope in patients with bifascicular block (BFB).
  • The intermittent nature of AV block poses challenges for electrocardiogram (ECG) documentation.
  • Bradycardia-detecting pacemakers offer a potential solution for investigating syncope in BFB patients.

Purpose of the Study:

  • To evaluate the utility of bradycardia-detecting pacemakers in identifying high-degree AV block in BFB patients with syncope.
  • To determine the time course between syncopal episodes and the development of documented high-degree AV block.

Main Methods:

  • Prospective study of 27 patients with BFB and syncope.
  • Implantation of a single-chamber ventricular-based pacemaker with bradycardia-detecting capability.
  • Bradycardia defined as heart rate < 30 bpm for ≥ 6 seconds.

Main Results:

  • A bradycardia event was detected in 52% of patients during a median 60-month follow-up.
  • 13 of these patients (93%) also had documented high-degree AV block.
  • High-degree AV block was documented within 24 months in 77% of patients with detected bradycardia, an annual incidence of 19% in the first 2 years.

Conclusions:

  • Syncope in BFB patients is highly predictive of developing high-degree AV block within 24 months.
  • Pacemaker therapy is justified in these patients even without prior ECG verification of AV block.
  • Bradycardia-detecting pacemakers are effective tools for diagnosing the cause of syncope in BFB.
Abstract

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