Alternate Site Right Ventricular Pacing Permanent Pacemaker Therapy - PowerPoint PPT Presentation

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Alternate Site Right Ventricular Pacing Permanent Pacemaker Therapy

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Title: Alternate Site Right Ventricular Pacing Permanent Pacemaker Therapy


1
Alternate Site Right Ventricular Pacing Permanent
Pacemaker Therapy
  • Wen-Shin Lee, M.D.
  • Taipei Veterans General Hospital
  • National Yang-Ming University

2
Historical Review of Pacing Therapy
  • 1952 Dr. Paul Zoll - transcutaneous pacing
  • Fixed rate asynchronous pacemakers
  • Demand pacemakers
  • Programmable pacemakers
  • Dual chamber pacemakers
  • Rate-adaptive pacemakers
  • Approach to simulate the original physiological
    envirment of human heart

3
Physiological Pacing - Enigma
  • DDD/R pacing does not reduce death compared with
    VVI/R, and has surprisingly modest or event
    negligible benefits for progression of CHF and Af
  • AAI/R reduces the risk of Af, HF, and death
    compared with VVI/R and DDD/R in sick sinus
    dysfunction

4
DAVID trial
  • The study was terminated prematurely and
    unexpectedly because of an excess of CHF and
    deaths in the DDD/R arm

5
MOST trial
  • The risks of CHF hospitalization and Af could be
    directly linked to CumVP, regardless of pacing
    mode
  • More than 10 of patients will be hospitalized
    for CHF, and around 18 of patients will develop
    Af during follow-up if CumVP gt 90

6
MADIT II trial
  • Similar relationship between CumVP and CHF,
    VT/Vf, and death that was insensitive to ICD
    system and pacing mode

7
Ventricular Asynchrony
  • Native LBBB as an independent predictor of
    cardiac morbidity and mortality for CHF patients
  • Am Heart J 20021431085-91
  • Am Heart J 2002143398-405
  • Iatrogenic LBBB induced by RV apical pacing also
    as an predictor of cardiac morbidity and
    mortality for CHF patients
  • DAVID trial
  • MOST trial
  • MADIT II trial

8
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9
Sweeney MO. J Am Coll Cardiol. 200647(2)282-8.
10
Adverse Effect of Asynchronous Ventricular
Activation
  • Less effective and energetically less efficient
    contraction of LV
  • Redistribution of mechanical work, perfusion, and
    O2 demand within the LV wall
  • Reduction in regional myocardial perfusion and O2
    consumption near the pacing site
  • The hemodynamic consequences are reduction in
    contractility and relaxation

11
Adverse Effect of Asynchronous Ventricular
Activation
  • Early signs of cellular and molecular adaptation
    of disturbed activation are abnormal
    repolarization and reduction in EF within hours
    of RV apex pacing
  • Alterations in potassium and calcium channels
  • Longer-lasting RV pacing results in ventricular
    dilatation and asymmetric LV hypertrophy
  • Cellular derangements such as down-regulation of
    protein involved Ca homeostasis and impulse
    conduction
  • Dystrophic calcifications, disorganized
    mitochondria and myofibrillar cellular disarray

12
Siu CW, et al. Prog Cardiovasc Dis.
200851(2)171-82
13
  • If the RV apex is bed, where is the better site
    of pacing choice?
  • RVOT
  • RV septum
  • Direct His-bundle pacing
  • LV pacing through coronary sinus
  • Multiple-site pacing
  • RV multiple-site pacing
  • Bi-ventricular pacing

14
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15
Problems About Alternate-site RV Pacing Studies
  • Who will get significant clinical benefit of
    alternate-RV pacing, if there is real benefit
    exist?
  • Asymptomatic HF or borderline LV function?
  • Patients with structure heart disease but
    preserved LV function, such as old MI or HCVD?
  • Patients will dependent on the PPM?
  • How long the should we spend on observation for
    the difference happened?
  • Where is the best practical pacing site?
  • Universal position or individualized position?
  • J Am Coll Cardiol 2006481634-41
  • Issue about RVOT pacing
  • Electrophysiological view or anatomical view of
    RVOT?
  • Which part of RVOT? Septum, anterior wall, or
    free wall?

16
Right Ventricular Outflow Tract -
17
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18
Right Ventricular Outflow Tract
19
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20
Sweeney MO. J Am Coll Cardiol. 200647(2)282-8.
21
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