The effects of right ventricular pacing in the heart failure population

  • Douglas Elder

    Student thesis: Doctoral ThesisDoctor of Medicine


    Pacemaker implantation remains the sole treatment options for patients
    with bradycardia. The devices have evolved over the years, however recent
    studies of implantable defibrillators suggested that increased levels of
    pacing at the right ventricular apex (the conventional site) may be
    associated with worse outcomes in patients with impaired left ventricular
    systolic function.
    An initial observational database linkage study was performed to investigate
    the prevalence of heart failure in patients referred for pacemaker insertion.
    This identified a significant portion of patients (19%) had heart failure and
    were potentially at risk. Further study was undertaken in patients without
    heart failure to investigate the effects of right ventricular (RV) apical pacing
    on endothelial function. 22 patients with sino-atrial node disease were
    exposed to high degrees of RV pacing and minimal RV pacing in a crossover
    study for 1 week each. This demonstrated significant impairment of
    endothelial function in the arm with a high degree of RV pacing.
    A subsequent study investigated the impact of biventricular pacing
    compared to RV pacing again in a cross over design. Patients were implanted with a biventricular device and randomised to RV only or biventricular
    pacing. Biventricular pacing was associated with significantly enhanced 6
    minute hall walk distance together with improved quality of life and less
    impairment of endothelial function and reduction of hs-CRP when compared
    to biventricular pacing.
    Finally a further retrospective data-linkage study demonstrated that
    angiotensin receptor blocker or angiotensin converting enzyme inhibitor use
    was associated with improved mortality and less hospitalisation for heart
    failure in patients paced for complete heart block, who were likely to be
    exposed to high degrees of right ventricular pacing.
    In summary this thesis is a record of my study of the effects of pacemaker
    insertion in patients with impaired left ventricular systolic function. My
    research has demonstrated the potential detrimental effects of right
    ventricular apical pacing and has identified potential therapeutic strategies
    of ameliorating these effects.
    Date of Award2013
    Original languageEnglish
    SupervisorAnna-Maria Choy (Supervisor)

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