Ganglionated Plexi Ablation for the Treatment of Atrial Fibrillation

Figure 1. Sympathetic and parasympathetic mechanism in the autonomic nervous system (ANS). Parasympathetic vagal activity (in red) inhibits noradrenaline (NE) which in turn inhibit acetylcholine release (ACh). Released ACh binds to M muscarinic receptors (M) and, through the inhibition of Protein G1, coupled to adenylate cyclase (AC). Released NE from postganglionic sympathetic nerve endings (dotted line) binds to β-adrenergic receptors (β) which activate AC increasing intracellular cyclic-AMP (cAMP).

Figure 2. Different morphology of neurons found in ganglionated plexi (GP) sites in humans. There are three types of neurons that are populated in GP sites. These are either unipolar (brown, blue) or multipolar (green, red) having either single (brown, blue, green) or multiple (red) processes.

Figure 3. Posterior view of the atria showing the interactions between neural pathways. (A): Arrows indicate the direction of impulse and the connections of the left vagosympathetic trunk (LVS) and right vagosympathetic trunk (RVS) with the anterior right (AR) and superior left (SL) GPs. These pathways have been shown to modulate the effects of the sinoatrial node (SA) node and attenuate sinus rate slowing. (B): Arrows indicate the direction of impulse and connections involving the LVS and RVS trunks, with the SL, AR and inferior right (IR) GP’s. These pathways have been shown to influence atrioventricular node (AV) node function and ventricular rate response. The inferior left GP (ILGP) acts as a pivotal element in the connection pathway to the AV node.

Figure 4. GP’s targeted for ablation. A posterior view of the heart showing all the main ganglionated plexi sites essential for ablation. (A) These include the transverse sinus (in purple) and superior right (in green) located between aorta (AO) and superior vena cava (SVC). (B) The oblique sinus GPs (in yellow) are situated supero-anterior to the right superior pulmonary vein (PV) (ARPV) and infero-posterior region of the right inferior PV (IRPV). The left superior (in orange) can be found medial to the left superior PV (SLPV). Vein of Marshall (in red) is another target ablation region within the ligament of Marshall. Pt, pulmonary trunk.