on April 24, 2009
Published online before print April 24, 2009, doi: 10.1161/CIRCEP.108.810689
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Original Article |
An Acute Experimental Model Demonstrating Two Different Forms of Sustained Atrial Tachyarrhythmias
1 Fuwai Hospital, Beijing, China;
2 University of Oklahoma, Health Sciences Center, Oklahoma City, Oklahoma;
3 Renmin Hospital of Wuhan University, Wuhan, China;
4 Third Hospital of Beijing University, Beijing, China
5 E-mail: benjamin-scherlag{at}ouhsc.edu
Background—To develop an acute experimental model showing both focal and macro-reentrant sustained AF.
Methods and Results—In 31 anesthetized dogs, bilateral thoracotomies allowed the attachment of electrode catheters at the right and left superior pulmonary veins (PVs); atrial free walls, and atrial appendages. Acetylcholine (Ach), 100mM, was topically applied to either appendage. Sequential radiofrequency ablation was achieved for the ganglionated plexi (GP) found adjacent to the 4 PVs. In 12 separate studies a propafenone bolus, 2mg/kg, was given before and after GP ablations at the start of Ach induced AF. Ach caused abrupt onset of AF (n=22) or induced AF by burst pacing (n=9) which lasted 
10 min. Rapid, regular or fractionated atrial electrograms were consistently seen (average cycle length (CL) = 37±7 ms) at the appendages vs. CLs of 114±23 ms at other atrial sites. After ablations of GP, AF abruptly terminated (n=25). In 6 dogs sustained atrial tachyarrhythmias (ATa) continued. Pacing at specific atrial sites organized electrograms of one atrium or also captured the other atrium. The latter resulted in termination when pacing was stopped in 4 of these 6 experiments. Propafenone did not change the duration of focal AF prior to GP ablation (17±9 min vs 14±8 min, control, p=0.6) but terminated reentrant ATa (12±3 vs 2±1 min, p=0.0009).
Conclusion—Prior to GP ablation Ach (100mM) induced sustained AF characterized by rapid, focal firing. GP ablations were associated with loss of focal firing and regularization of electrograms in both atria prior to termination. Propafenone failed to terminate focal AF but rapidly terminated entrainable macro-reentrant ATa.
Key Words: ablation • acetylcholine • antiarrhythmia agents • fibrillation • nervous system, autonomic • atrial fibrillation • atrial tachyarrhythmia • autonomic nervous system
Related Article
Circ Arrhythm Electrophysiol 2009 2: 345-348.
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