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Long-Term Mechanical Consequences of Permanent Right Ventricular Pacing: Effect of Pacing Site

Authors

  • DARRYL P. LEONG M.B.B.S.,

    1. Cardiovascular Research Centre, Department of Cardiology, Royal Adelaide Hospital
    2. The Disciplines of Medicine and Physiology, University of Adelaide, Adelaide, Australia
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  • ANNE-MARIE MITCHELL R.N.,

    1. Cardiovascular Research Centre, Department of Cardiology, Royal Adelaide Hospital
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  • INGRID SALNA,

    1. Cardiovascular Research Centre, Department of Cardiology, Royal Adelaide Hospital
    2. The Disciplines of Medicine and Physiology, University of Adelaide, Adelaide, Australia
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  • ANTHONY G. BROOKS Ph.D,

    1. Cardiovascular Research Centre, Department of Cardiology, Royal Adelaide Hospital
    2. The Disciplines of Medicine and Physiology, University of Adelaide, Adelaide, Australia
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  • GAUTAM SHARMA M.D.,

    1. Cardiovascular Research Centre, Department of Cardiology, Royal Adelaide Hospital
    2. The Disciplines of Medicine and Physiology, University of Adelaide, Adelaide, Australia
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  • HAN S. LIM M.B.B.S.,

    1. Cardiovascular Research Centre, Department of Cardiology, Royal Adelaide Hospital
    2. The Disciplines of Medicine and Physiology, University of Adelaide, Adelaide, Australia
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  • MUAYAD ALASADY M.B.B.S.,

    1. Cardiovascular Research Centre, Department of Cardiology, Royal Adelaide Hospital
    2. The Disciplines of Medicine and Physiology, University of Adelaide, Adelaide, Australia
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  • MALCOLM BARLOW M.B.B.S.,

    1. Department of Cardiology, John Hunter Hospital, Newcastle, Australia
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  • JAMES LEITCH M.B.B.S.,

    1. Department of Cardiology, John Hunter Hospital, Newcastle, Australia
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  • PRASHANTHAN SANDERS M.B.B.S., Ph.D,

    1. Cardiovascular Research Centre, Department of Cardiology, Royal Adelaide Hospital
    2. The Disciplines of Medicine and Physiology, University of Adelaide, Adelaide, Australia
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  • GLENN D. YOUNG M.B.B.S.

    1. Cardiovascular Research Centre, Department of Cardiology, Royal Adelaide Hospital
    2. The Disciplines of Medicine and Physiology, University of Adelaide, Adelaide, Australia
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  • Presented in part at the 2009 Annual Scientific Sessions of the American Heart Association and published in abstract form in Circulation 2009; 120: S715.

  • Medtronic Australasia provided financial support for undertaking the study. Dr. Leong is supported by a Medical Postgraduate Scholarship funded jointly by the National Health and Medical Research Council of Australia and the National Heart Foundation of Australia. Drs. Brooks and Sanders are supported by the National Heart Foundation of Australia. Drs. Lim and Alasady are supported by Divisional Scholarships and the Earl Bakken Electrophysiology Scholarship from the University of Adelaide. Dr. Lim is supported by a Medical Postgraduate Scholarship from the National Health and Medical Research Council of Australia.

  • Dr. Sanders reports having served on the advisory board of and having received lecture fees and research funding from Bard Electrophysiology, Biosense-Webster, Medtronic, and St. Jude Medical. Other authors: No disclosures.

Address for correspondence: Prashanthan Sanders, M.B.B.S., Ph.D., Department of Cardiology, Cardiovascular Research Centre, Cardiovascular Investigation Unit, Royal Adelaide Hospital, North Terrace, Adelaide, SA 5000, Australia. Fax: +61-8-8222-2722. E-mail: prash.sanders@adelaide.edu.au

Abstract

Optimal Right Ventricular PacingIntroduction: Long-term right ventricular apical (RVA) pacing has been associated with adverse effects on left ventricular systolic function; however, the comparative effects of right ventricular outflow tract (RVOT) pacing are unknown. Our aim was therefore to examine the long-term effects of septal RVOT versus RVA pacing on left ventricular and atrial structure and function.

Methods: Fifty-eight patients who were prospectively randomized to long-term pacing either from the right ventricular apex or RVOT septum were studied echocardiographically. Left ventricular (LV) and atrial (LA) volumes were measured. LV 2D strain and tissue velocity images were analyzed to measure 18-segment time-to-peak longitudinal systolic strain and 12-segment time-to-peak systolic tissue velocity. Intra-LV synchrony was assessed by their respective standard deviations. Interventricular mechanical delay was measured as the difference in time-to-onset of systolic flow in the RVOT and LV outflow tract. Septal A’ was measured using tissue velocity images.

Results: Following 29 ± 10 months pacing, there was a significant difference in LV ejection fraction (P < 0.001), LV end-systolic volume (P = 0.007), and LA volume (P = 0.02) favoring the RVOT-paced group over the RVA-paced patients. RVA-pacing was associated with greater interventricular mechanical dyssynchrony and intra-LV dyssynchrony than RVOT-pacing. Septal A’ was adversely affected by intra-LV dyssynchrony (P < 0.05).

Conclusions: Long-term RVOT-pacing was associated with superior indices of LV structure and function compared with RVA-pacing, and was associated with less adverse LA remodeling. If pacing cannot be avoided, the RVOT septum may be the preferred site for right ventricular pacing. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1120-1126)

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