Title: Alternate Site Right Ventricular Pacing Permanent Pacemaker Therapy
1Alternate Site Right Ventricular Pacing Permanent
Pacemaker Therapy
- Wen-Shin Lee, M.D.
- Taipei Veterans General Hospital
- National Yang-Ming University
2Historical 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
3Physiological 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
4DAVID trial
- The study was terminated prematurely and
unexpectedly because of an excess of CHF and
deaths in the DDD/R arm
5MOST 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
6MADIT II trial
- Similar relationship between CumVP and CHF,
VT/Vf, and death that was insensitive to ICD
system and pacing mode
7Ventricular 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
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9Sweeney MO. J Am Coll Cardiol. 200647(2)282-8.
10Adverse 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
11Adverse 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
12Siu 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
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15Problems 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?
16Right Ventricular Outflow Tract -
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18Right Ventricular Outflow Tract
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20Sweeney MO. J Am Coll Cardiol. 200647(2)282-8.
21Thanks for your attention