Document Detail

Optimised rate-responsive pacing does not improve either right ventricular haemodynamics or exercise capacity in adults with a systemic right ventricle.
MedLine Citation:
PMID:  20456818     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Inappropriate heart rate response to exercise - chronotropic incompetence - and exercise intolerance are common in patients with a systemic right ventricle. We aimed to assess the relationship between heart rate increase, oxygen consumption, and timing of the right ventricular cardiac cycle in this cohort.
METHODS: We prospectively studied nine patients with systemic right ventricles and pre-existing pacemakers using Doppler-echocardiography and treadmill exercise testing. Echocardiography was performed at increasing heart rates. Exercise tests were performed with baseline pacemaker settings and with optimised heart rate response in random order. In addition, eight age- and gender-matched controls underwent exercise testing using a similar exercise protocol.
RESULTS: Patients with a systemic right ventricle had significantly lower peak oxygen consumption compared to controls - 12.6 plus or minus 6.8 versus 31.4 plus or minus 6.6 metres per kilogram per minute (p = 0.0006) - at baseline and active pacemaker reprogramming failed to increase peak oxygen consumption in this cohort - 12.6 plus or minus 6.8 versus 12.4 plus or minus 4.9 millilitres per kilogram per minute (p = NS) at baseline and with reprogramming, respectively. We found not only a marked increase in total isovolumic time but also a significant reduction in total filling time and the aortic velocity time integral, p-value is less than 0.001 for all, at higher heart rates compared to baseline conditions.
CONCLUSION: This study suggests that despite chronotropic incompetence at baseline, rate-responsive pacing does not improve exercise capacity in patients with a systemic right ventricle. It further indicates that high heart rates may be detrimental in these patients by reducing diastolic filling and stroke volume. These findings may have clinical implications when considering implantation of a permanent pacemaker in this cohort.
Anselm Uebing; Gerhard-Paul Diller; Wei Li; Mark Maskell; Konstantinos Dimopoulos; Michael A Gatzoulis
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-05-11
Journal Detail:
Title:  Cardiology in the young     Volume:  20     ISSN:  1467-1107     ISO Abbreviation:  Cardiol Young     Publication Date:  2010 Oct 
Date Detail:
Created Date:  2010-09-02     Completed Date:  2011-01-25     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9200019     Medline TA:  Cardiol Young     Country:  England    
Other Details:
Languages:  eng     Pagination:  485-94     Citation Subset:  IM    
Adult Congenital Heart Centre, Royal Brompton Hospital and the National Heart and Lung Institute at Imperial College, London, United Kingdom.
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MeSH Terms
Echocardiography, Doppler
Exercise Test
Exercise Tolerance / physiology*
Follow-Up Studies
Heart Atria / abnormalities*,  physiopathology,  ultrasonography
Heart Defects, Congenital / physiopathology*,  therapy,  ultrasonography
Heart Rate / physiology*
Middle Aged
Oxygen Consumption
Pacemaker, Artificial*
Prospective Studies
Treatment Outcome
Ventricular Dysfunction, Right / physiopathology*,  therapy,  ultrasonography
Young Adult
Grant Support
//British Heart Foundation

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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