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Distal atrioventricular conduction system function

R A Bauernfeind, W J Welch, S L Brownstein

    Cardiology Clinics
    |August 1, 1986
    PubMed

    Insights

    Electrophysiologic studies are rarely needed for chronic bifascicular block, as complete heart block progression is uncommon. Current use focuses on specific cases of heart block or unexplained fainting.

    Area of Science:

    • Cardiology
    • Electrophysiology
    • Internal Medicine

    Background:

    • Chronic bifascicular block was historically associated with high risk of complete atrioventricular (AV) block and sudden death.
    • Electrophysiologic studies, including H-V interval measurement, were proposed to identify high-risk patients for prophylactic treatment.

    Purpose of the Study:

    • To evaluate the current role of electrophysiologic studies in managing patients with chronic bifascicular block.
    • To reassess the risk of progression to complete AV block and its impact on mortality.

    Main Methods:

    • Review of clinical investigations and electrophysiologic data in patients with chronic bifascicular block.
    • Analysis of outcomes, including progression to complete AV block and cardiovascular mortality.

    Main Results:

    • Progression to complete AV block in chronic bifascicular block is rare.
    • Cardiovascular mortality, including sudden death, is significant but primarily linked to underlying organic heart disease, not AV block progression.
    • Electrophysiologic studies are useful for locating the site of documented AV block and evaluating unexplained syncope.

    Conclusions:

    • The feared progression to complete AV block is uncommon in chronic bifascicular block.
    • Mortality in these patients is mainly due to underlying heart disease.
    • Electrophysiologic evaluation is reserved for specific indications like documented AV block or unexplained syncope.

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