TY - JOUR
T1 - Endocardial stimulation of efferent parasympathetic nerves to the atrioventricular node in humans
T2 - Optimal stimulation sites and the effects of digoxin
AU - Quan, Kara J.
AU - Van Hare, George F.
AU - Biblo, Lee A.
AU - Mackall, Judith A.
AU - Carlson, Mark D.
PY - 2001
Y1 - 2001
N2 - The purposes of this study were to identify optimal sites of stimulation of efferent parasympathetic nerve fibers to the human atrioventricular node via an endocardial catheter and to investigate the interaction between digoxin and vagal activation at the end organ. Methods: The ventricular rate was measured during atrial fibrillation, prior to and during parasympathetic nerve stimulation, in 8 patients taking digoxin and in 10 controls. High frequency electrical stimuli were delivered via an hexapolar or quadripolar electrode catheter, placed at the posteroseptal right atrium near the atrioventricular node (n = 18 patients) or in the coronary sinus (n = 12 of 18 patients). In 4 patients, stimulation was repeated after intravenous administration of 1 to 2 mg of atropine. Results: Nerve stimulation prolonged the R-R interval in all patients. Stimulation close to the posteroseptal right atrium led to maximal atrioventricular nodal slowing. The mean R-R intervals at baseline and during parasympathetic nerve stimulation (60 mA) from the posteroseptal right atrium and the proximal coronary sinus were 581 ± 79 ms, 2440 ± 466, and 900 ± 228 ms respectively (p = 0.0001). The response to nerve stimulation was greater in patients taking digoxin than in patients not taking the drug (p = 0.02). Junctional rhythm occurred during nerve stimulation in 8/8 patients taking digoxin and 0/10 not taking the drug (p = 0.0001). The response to stimulation was eliminated after atropine (p = 0.01). Conclusions: Parasympathetic nerves to the atrioventricular node were stimulated from the proximal coronary sinus as well as the posteroseptal right atrium. Stimulation at the posteroseptal right atrium resulted in the greatest response, and digoxin enhanced this response. The augmented response suggests that an interaction may exist between parasympathetic stimulation and digoxin at the end organ.
AB - The purposes of this study were to identify optimal sites of stimulation of efferent parasympathetic nerve fibers to the human atrioventricular node via an endocardial catheter and to investigate the interaction between digoxin and vagal activation at the end organ. Methods: The ventricular rate was measured during atrial fibrillation, prior to and during parasympathetic nerve stimulation, in 8 patients taking digoxin and in 10 controls. High frequency electrical stimuli were delivered via an hexapolar or quadripolar electrode catheter, placed at the posteroseptal right atrium near the atrioventricular node (n = 18 patients) or in the coronary sinus (n = 12 of 18 patients). In 4 patients, stimulation was repeated after intravenous administration of 1 to 2 mg of atropine. Results: Nerve stimulation prolonged the R-R interval in all patients. Stimulation close to the posteroseptal right atrium led to maximal atrioventricular nodal slowing. The mean R-R intervals at baseline and during parasympathetic nerve stimulation (60 mA) from the posteroseptal right atrium and the proximal coronary sinus were 581 ± 79 ms, 2440 ± 466, and 900 ± 228 ms respectively (p = 0.0001). The response to nerve stimulation was greater in patients taking digoxin than in patients not taking the drug (p = 0.02). Junctional rhythm occurred during nerve stimulation in 8/8 patients taking digoxin and 0/10 not taking the drug (p = 0.0001). The response to stimulation was eliminated after atropine (p = 0.01). Conclusions: Parasympathetic nerves to the atrioventricular node were stimulated from the proximal coronary sinus as well as the posteroseptal right atrium. Stimulation at the posteroseptal right atrium resulted in the greatest response, and digoxin enhanced this response. The augmented response suggests that an interaction may exist between parasympathetic stimulation and digoxin at the end organ.
KW - Atrioventricular node
KW - Digoxin
KW - Electrical stimulation
KW - Vagus nerve
UR - http://www.scopus.com/inward/record.url?scp=0035007234&partnerID=8YFLogxK
U2 - 10.1023/A:1011473307112
DO - 10.1023/A:1011473307112
M3 - Article
C2 - 11342750
AN - SCOPUS:0035007234
SN - 1383-875X
VL - 5
SP - 145
EP - 152
JO - Journal of Interventional Cardiac Electrophysiology
JF - Journal of Interventional Cardiac Electrophysiology
IS - 2
ER -