Ectopic atrial arrhythmias arising from canine thoracic veins during in vivo stellate ganglia stimulation.
The purpose of the present study was to determine whether thoracic veins may act as ectopic pacemakers and whether nodelike cells and rich sympathetic innervation are present at the ectopic sites. We used a 1,792-electrode mapping system with 1-mm resolution to map ectopic atrial arrhythmias in eight normal dogs during in vivo right and left stellate ganglia (SG) stimulation before and after sinus node crushing. SG stimulation triggered significant elevations of transcardiac norepinephrine levels, sinus tachycardia in all dogs, and atrial tachycardia in two of eight dogs. Sinus node crushing resulted in a slow junctional rhythm (51 +/- 6 beats/min). Subsequent SG stimulation induced 20 episodes of ectopic beats in seven dogs and seven episodes of pulmonary vein tachycardia in three dogs (cycle length 273 +/- 35 ms, duration 16 +/- 4 s). The ectopic beats arose from the pulmonary vein (n = 11), right atrium (n = 5), left atrium (n = 2), and the vein of Marshall (n = 2). There was no difference in arrhythmogenic effects of left vs. right SG stimulation (13/29 vs. 16/29 episodes, P = nonsignificant). There was a greater density of periodic acid Schiff-positive cells (P < 0.05) and sympathetic nerves (P < 0.05) at the ectopic sites compared with other nonectopic atrial sites. We conclude that, in the absence of a sinus node, thoracic veins may function as subsidiary pacemakers under heightened sympathetic tone, becoming the dominant sites of initiation of focal atrial arrhythmias that arise from sites with abundant sympathetic nerves and periodic acid Schiff-positive cells.
Tan
Alex Y
AY
Division of Cardiology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
Zhou
Shengmei
S
Jung
Byung Chun
BC
Ogawa
Masahiro
M
Chen
Lan S
LS
Fishbein
Michael C
MC
Chen
Peng-Sheng
PS
D000818:Animals; D001683:Biological Clocks; D018780:Body Surface Potential Mapping; D004285:Dogs; D004558:Electric Stimulation; D004837:Epinephrine / Q000097:blood; D007090:Image Interpretation, Computer-Assisted; D009638:Norepinephrine / Q000097:blood; D010503:Periodic Acid-Schiff Reaction; D011667:Pulmonary Veins / Q000294:innervation / Q000503:physiopathology; D012849:Sinoatrial Node / Q000503:physiopathology; D013233:Stellate Ganglion / Q000503:physiopathology*; D017779:Sympathetic Fibers, Postganglionic / Q000378:metabolism / Q000503:physiopathology*; D013612:Tachycardia, Ectopic Atrial / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D013616:Tachycardia, Sinus / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D013909:Thorax / Q000098:blood supply*; D013997:Time Factors; D014680:Veins / Q000294:innervation / Q000503:physiopathology
D009638:Norepinephrine; D004837:Epinephrine