Document Detail

Evaluation of direct respiratory modulation of the QT interval variability.
MedLine Citation:
PMID:  10392380     Owner:  NLM     Status:  MEDLINE    
To investigate the direct respiration-mediated vagal modulation of the QT interval variability, spectral analyses of the RTp interval (from the R wave peak to the T wave peak) variability (RTpV) and the RR interval variability (RRV) were performed in 12 subjects with normal ventricular repolarization under three conditions while the respiration frequency was kept at 0.2 Hz: during sinus rhythm, during fixed atrial pacing, and during fixed atrial pacing with autonomic blockade. The cross-spectrum between the RRV and RTpV was quantified by the squared coherence. During sinus rhythm the RRV power spectrum showed two peaks: a broad peak in the low frequency (LF) band and a sharp peak at 0.2 Hz which corresponded to the controlled respiration frequency. The RTpV power spectrum showed corresponding peaks to the RRV peaks in both the LF and high frequency (HF) bands with high coherence (mean maximum values of the squared coherence in the LF band 0.59 +/- 0.22, and in the HF band 0.74 +/- 0.14). During atrial pacing mean total power of the RTpV decreased from during sinus rhythm (from 16.3 +/- 5.6 ms2 to 12.9 +/- 5.4 ms2, P < 0.05) and the RTpV spectral peaks were abolished in both the LF and HF bands concordant with disappearance of the RRV peaks. Autonomic blockade gave no additional change to the RTpV power spectrum independently of the RRV during fixed atrial pacing. The present study suggested that the direct respiration-mediated vagal modulation may not affect the short-term variability of the QT interval in subjects without repolarization abnormality.
T Emori; T Ohe
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Pacing and clinical electrophysiology : PACE     Volume:  22     ISSN:  0147-8389     ISO Abbreviation:  Pacing Clin Electrophysiol     Publication Date:  1999 Jun 
Date Detail:
Created Date:  1999-09-08     Completed Date:  1999-09-08     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7803944     Medline TA:  Pacing Clin Electrophysiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  842-8     Citation Subset:  IM    
Department of Cardiovascular Medicine, Okayama University Medical School, Japan.
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MeSH Terms
Autonomic Nervous System / physiopathology
Catheter Ablation
Electrocardiography* / instrumentation
Fourier Analysis
Heart / innervation*
Heart Rate / physiology*
Heart Ventricles / physiopathology
Respiratory Mechanics / physiology*
Signal Processing, Computer-Assisted / instrumentation
Tachycardia, Supraventricular / physiopathology,  surgery
Vagus Nerve / physiopathology*

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

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