Document Detail

Changes in QT and Q-aT intervals induced by mental and physical stress with fixed rate and atrial triggered ventricular inhibited cardiac pacing.
MedLine Citation:
PMID:  2462219     Owner:  NLM     Status:  MEDLINE    
We have investigated the influence of mental stress and physical stress, i.e., exercise, on the QT and Q-aT intervals (measured from the pacemaker stimulus to the end or the apex, respectively, of the T wave). The study was made on ten patients with high degree atrioventricular block treated with AV universal (DDD) pacemakers. These were programmed to a fixed rate ventricular (VVI) or an atrial triggered (VDD) function for different parts of the study. An arithmetic mental stress test and a bicycle exercise test were performed with each mode of pacing. In the VVI pacing mode, the atrial rate increased by 11% during mental stress and by 46% during exercise. There was a significant shortening of QT and Q-aT intervals with both types of stress. With VDD pacing, mental stress induced a 12% increase in rate and a significant shortening of QT and Q-aT. The paced rate increased by 50% during the exercise test. This increase in ventricular rate was associated with the most marked changes in QT and Q-aT intervals. Thus, both types of stress cause a significant shortening of the QT and Q-aT interval even in the absence of a simultaneous increase in ventricular rate. When the latter is allowed to increase during VDD pacing, both intervals shorten considerably more. There was a marked inter-individual variability in the response to both types of stress. These findings are of importance with regard to the QT sensing rate responsive pacemaker which can be expected to respond to mental stress in most patients, but that response might be unpredictable in the individual.
A Hedman; R Nordlander
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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:  11     ISSN:  0147-8389     ISO Abbreviation:  Pacing Clin Electrophysiol     Publication Date:  1988 Oct 
Date Detail:
Created Date:  1989-01-18     Completed Date:  1989-01-18     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  7803944     Medline TA:  Pacing Clin Electrophysiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1426-31     Citation Subset:  IM    
Department of Medicine, Karolinska Hospital, Stockholm, Sweden.
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MeSH Terms
Cardiac Pacing, Artificial / methods*
Exercise Test
Heart Atria
Heart Block / therapy
Heart Rate*
Heart Ventricles
Middle Aged
Stress, Physiological / physiopathology*
Stress, Psychological / physiopathology*

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