Document Detail

Rapid fluctuations in atrial fibrillatory electrophysiology detected during controlled respiration.
MedLine Citation:
PMID:  16014618     Owner:  NLM     Status:  MEDLINE    
Heart rate during sinus rhythm is modulated through the autonomic nervous system, which generates short-term oscillations. The high-frequency components in these oscillations are associated with respiration, causing sinus arrhythmia, mediated by the parasympathetic nervous system. In this study, we evaluated whether slow, controlled respiration causes cyclic fluctuations in the frequency of the fibrillating atria. Eight patients (four women; median age 63 yr, range 53-68 yr) with chronic atrial fibrillation (AF) and third-degree atrioventricular block treated by permanent pacemaker were studied. ECG was recorded during baseline rest, during 0.125-Hz frequency controlled respiration, and finally during controlled respiration after full vagal blockade. We calculated fibrillatory frequency using frequency analysis of the fibrillatory ECG for overlapping 2.5-s segments; spectral analysis of the resulting frequency trend was performed to determine the spectrum of variations of fibrillatory frequency. Normalized spectral power at respiration frequency increased significantly during controlled respiration from 1.4 (0.76-2.0) (median and range) at baseline to 2.7 (1.2-5.8) (P = 0.01). After vagal blockade, the power at respiration frequency decreased to 1.2 (0.23-2.8) (P = 0.01). Controlled respiration causes cyclic fluctuations in the AF frequency in patients with long-duration AF. This phenomenon seems to be related to parasympathetic modulations of the AF refractory period.
Fredrik Holmqvist; Martin Stridh; Johan E P Waktare; Johan Brandt; Leif Sörnmo; Anders Roijer; Carl J Meurling
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  289     ISSN:  0363-6135     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2005 Aug 
Date Detail:
Created Date:  2005-07-14     Completed Date:  2005-09-08     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H754-60     Citation Subset:  IM    
Department of Cardiology, Lund Univ. Hospital, SE-221 85 Lund, Sweden.
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MeSH Terms
Atrial Fibrillation / complications,  diagnosis,  physiopathology*
Chronic Disease
Heart Block / complications,  therapy
Middle Aged
Nerve Block
Pacemaker, Artificial
Respiratory Mechanics*
Vagus Nerve

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

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