In:
American Journal of Physiology-Heart and Circulatory Physiology, American Physiological Society, Vol. 281, No. 2 ( 2001-08-01), p. H865-H872
Abstract:
In vitro experiments have shown that the complexity of atrioventricular nodal (AVN) conduction dynamics increases with heart rate. Although complex AVN dynamics (e.g., alternans) have been observed clinically, human AVN dynamics during rapid pacing have not been systematically investigated. We studied such dynamics during ventricular-triggered atrial pacing in 37 patients with normal AVN function (18 patients with dual AVN pathway physiology and 19 patients without). Alternans, which always resulted from single pathway conduction, occurred in 18 patients. In 16 patients (3 of whom also had alternans), quasisinusoidal AVN conduction oscillations occurred (mean frequency 0.02 Hz); such oscillations have not been previously reported. There were no significant differences in the dynamics for patients with or without dual AVN pathways. To illuminate the governing dynamic mechanism, a second atrial pacing trial was performed on 12 patients after autonomic blockade. Blockade facilitated alternans but inhibited oscillations. This study suggests that rapid AVN excitation in vivo can lead to autonomically mediated AVN conduction oscillations or single pathway alternans that are a function of inherent nonlinear dynamic AVN tissue properties.
Type of Medium:
Online Resource
ISSN:
0363-6135
,
1522-1539
DOI:
10.1152/ajpheart.2001.281.2.H865
Language:
English
Publisher:
American Physiological Society
Publication Date:
2001
detail.hit.zdb_id:
1477308-9
SSG:
12
