Document Detail

Do we need a reflex tachycardia to stand up?
MedLine Citation:
PMID:  16176536     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Sophisticated atrio-ventricular pacing models are designed to integrate the pacemaker into cardiovascular autonomic control to react appropriately to the cardiovascular demands. Such an approach might be beneficial for patients with vasovagal responses to counterbalance the upright fall in arterial blood pressure by a pacing rate increase. We hypothesized that this approach would improve the cardiovascular response to standing in comparison with a regular pacing mode. METHODS: Two 5-minute tilt tests were performed in a random order in 5 patients with a pacemaker (CLS-INOS(2)) for sinus node disease and atrio-ventricular block. One tilt test was performed in fixed pacing rate (DDD), the other one was performed in close loop stimulation (CLS), which allowed an upright rate-rise pacing. Heart rate, systolic blood pressure, and cardiac output (modelflow) were recorded on a beat-by-beat basis. RESULTS: Changes of systolic blood pressure and cardiac output in response to upright posture were not significantly different between DDD and CLS modes (2.7 +/- 13.2 vs 10.1 +/- 12.9 mmHg and -0.8 +/- 0.3 vs -1.1 +/- 0.4 L/min, respectively). But upright posture led to a tachycardia of more than 30 bpm in 3 patients in CLS mode and to a fall in systolic blood pressure greater than 20 mmHg in 3 patients in CLS mode and only in one patient in DDD mode. CONCLUSION: Systolic blood pressure and cardiac output are not improved by the upright tachycardia and upright blood pressure response is actually worsened when an upright rate-rise pacing is used. Thus, it appears that tachycardia alone cannot compensate for an upright fall in blood pressure.
Jacques-Olivier Fortrat; Catherine Lemarie; Elisabeth Bellard; Jacques Victor
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Pacing and clinical electrophysiology : PACE     Volume:  28     ISSN:  0147-8389     ISO Abbreviation:  Pacing Clin Electrophysiol     Publication Date:  2005 Sep 
Date Detail:
Created Date:  2005-09-22     Completed Date:  2006-01-03     Revised Date:  2009-11-03    
Medline Journal Info:
Nlm Unique ID:  7803944     Medline TA:  Pacing Clin Electrophysiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  962-7     Citation Subset:  IM    
Laboratoire de Physiologie, Faculté de Médecine, Centre Hospitalo-Universitaire, Faculté de Médecine, 49045 Angers Cedex, France.
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MeSH Terms
Aged, 80 and over
Blood Pressure / physiology
Cardiac Output / physiology
Heart Block / physiopathology,  therapy*
Heart Rate / physiology
Middle Aged
Pacemaker, Artificial*
Sick Sinus Syndrome / physiopathology,  therapy*
Statistics, Nonparametric
Syncope, Vasovagal / physiopathology*
Tachycardia / physiopathology*
Tilt-Table Test

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

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