Effects of ganglionated plexi ablation on ventricular electrophysiological properties in normal hearts and after acute myocardial ischemia

Abstract

Background: Ganglionated plexi (GP) ablation has been shown to play an important role in atrial fibrillation (AF) initiation and maintenance. Also, GP ablation increases chances for prevention of AF recurrence. This study investigated the effects of GP ablation on ventricular electrophysiological properties in normal dog hearts and after acute myocardial ischemia (AMI).

Methods: Fifty anesthetized dogs were assigned into normal heart group (n=16) and AMI heart group (n=34). Ventricular dynamic restitution, effective refractory period (ERP), electrical alternans and ventricular fibrillation threshold (VFT) were measured before and after GP ablation in the normal heart group. In the AMI heart group, the incidence of ventricular arrhythmias and VFT were determined.

Results: In the normal heart group, GP ablation significantly prolonged ERP, facilitated electrical alternans but did not increase ERP dispersion, the slope of restitution curves and its spatial dispersion. Also, GP ablation did not cause significant change of VFT. In the AMI heart group, the incidence of ventricular arrhythmias after GP ablation was significantly higher than that in the control group or the GP plus stellate ganglion (SG) ablation group (P<0.05). Spontaneous VF occurred in 8/12, 1/10 and 2/12 dogs in the GP ablation group, the GP plus SG ablation group and the control group, respectively (P<0.05). VFT in the GP ablation group showed a decreased trend though a significant difference was not achieved compared with the control or the GP plus SG ablation group.

Conclusions: GP ablation increases the risk of ventricular arrhythmias in the AMI heart compared to the normal heart.

Keywords: AF; AMI; AP; APD; APD(90); Acute myocardial ischemia; CV; DI; ERP; GP; Ganglionated plexi ablation; ICANS; LVA; LVB; LVM; RVA; RVB; RVM; S(max); SG; VA; VF; VFT; VPC; VT; Ventricular electrophysiological property; action potential; action potential duration; acute myocardial ischemia; an APD at 90% repolarization; atrial fibrillation; coefficient of variation; diastolic interval; effective refractory period; ganglionated plexi; intrinsic cardiac autonomic nervous system; left ventricular apex; left ventricular base; right ventricular apex; right ventricular base; stellate ganglion; the maximum slope of restitution curve; the median area between LVA and LVB; the median area between RVA and RVB; ventricular arrhythmias; ventricular fibrillation; ventricular fibrillation threshold; ventricular premature contraction; ventricular tachycardia.