Autonomic modulation of ventricular rate in atrial
fibrillation.
Nagayoshi, Hirokazu, Tomas Janota, Katerina Hnatkova, A John Camm, and
Marek Malik.
Department of Cardiological Sciences, St. George's Hospital Medical
School, Cranmer Terrace, London, SW17 0RE, United Kingdom
APStracts 3:0487H, 1996.
This study investigated the changes of RR intervals in 23 patients (11
male, mean age 61) with persistent atrial fibrillation, in response
to several provocative manoeuvres including active postural change,
Valsalva manoeuvre, handgrip, and rhythm controlled respiration.
Averaged RR intervals were shortened immediately after postural
change (from 797+/-35 ms in supine to 677+/-27 ms in standing,
p<0.01) and recovered to 90% level within 100 seconds. During
Valsalva strain and handgrip, mean RRs were significantly shortened
(from 737+/-37 ms in sitting to 697+/-38 ms in Valsalva, from 773+/
-68 ms in sitting to 701+/-58 ms in handgrip, both p<0.01).
During rhythm controlled respiration, only 2 cases (10.5%) showed
power peaks in spectrograms of moving window averaged RR intervals at
the frequency corresponding to respiration rhythm. The ventricular
response to atrial fibrillation is influenced by the increase of
sympathetic and decrease of parasympathetic tone, but not necessarily
influenced by the increase of parasympathetic dominance. These
results suggest that even in atrial fibrillation patients, autonomic
nervous system modulates ventricular rate via atrioventricular node
and atrial tissue.
Received 11 September 1996; accepted in final form 7 November
1996.
APS Manuscript Number H821-6.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 31 December 1996