Acute effects of ganglionated plexi ablation on sinoatrial nodal and atrioventricular nodal functions

Ganglionated plexus (GP) ablation has been shown effective for eliminating atrial fibrillation (AF), the most common clinical tachyarrhythmia. However, the safety of destroying the main cardiac autonomic structures remains unclear. This study investigated the acute effects of GP ablation on the sinoatrial nodal (SAN) and atrioventricular nodal (AVN) functions in a canine model. In 10 open-chest dogs, multiple electrode catheters were sutured at both atria for recording and pacing. SAN and AVN function were evaluated. GP ablation caused no significant change of sinus rate immediately after GP ablation compared with the baseline state. After GP ablation, the sinus node recovery time (SNRT) and corrected SNRT did not show significant changes at long pacing cycle lengths (CLs), and only showed significant decrease at shorter pacing CLs. The AH interval at different pacing CLs, the Wenckebach atrioventricular block (AVB) CL, 2:1 AVB CL or the ventricular rate during AF were not significantly altered by GP ablations. Vagal suppression of SAN and AVN functions was eliminated by GP ablation. GP staining showed abundant choline acetyl transferase or tyrosine hydroxylase positive neurons. These findings suggest the functions of the SAN and AVN are mainly retained after GP ablation. These results may be partially related to destroying both parasympathetic and sympathetic elements in the GP by ablation.