Multifascicular block in cardiomyopathy. Incidence, localization by His bundle study and prognosis

Area of Science:

• Cardiology
• Electrophysiology

Background:

• Cardiomyopathy is associated with various conduction abnormalities.
• Bifascicular block, involving two of the three main conduction pathways, can occur in these patients.

Purpose of the Study:

• To investigate the prevalence and clinical significance of bifascicular block in patients with cardiomyopathy.
• To assess the short-term prognosis and electrophysiological characteristics of these patients.

Main Methods:

• Retrospective analysis of 70 cardiomyopathy patients' electrocardiograms.
• Evaluation of five patients with bifascicular block using His bundle electrocardiography and atrial pacing.

Main Results:

• Bifascicular block was found in 13% of patients (n=9).
• Common patterns included right bundle branch block with hemiblock and left bundle branch block with hemiblock.
• His bundle electrocardiography revealed His-Purkinje system block (prolonged HV interval) in four patients, with normal atrioventricular conduction (AH interval).

Conclusions:

• Bifascicular block occurs in a notable percentage of cardiomyopathy patients.
• Despite intraventricular conduction delays, short-term prognosis appears favorable, with no progression to advanced block or Stokes-Adams attacks.
• Atrial pacing demonstrated preserved atrioventricular conduction, suggesting a stable electrophysiological profile.