The effects of atrial ganglionated plexi stimulation on ventricular electrophysiology in a normal canine heart.

AIMS

Atrial ganglionated plexi (GP) have been shown to modulate atrial electrophysiology and play an important role in atrial fibrillation initiation and maintenance. The purpose of this study was to investigate the effects of atrial GP stimulation (GPS) on ventricular refractoriness, restitution properties and electrical alternans.

METHODS

In 12 anesthetized dogs, two multiple electrode catheters were sutured at left and right ventricular free walls for recording. Monophasic action potentials were recorded from six epicardial ventricular sites. Ventricular effective refractory period (ERP), action potential duration (APD) restitution properties and APD alternans were measured at baseline and during GPS.

RESULTS

Compared with baseline, GPS significantly prolonged ventricular ERP and APD at all sites and decreased their spatial dispersions (P < 0.05 for all). GPS also significantly flattened ventricular restitution curves and decreased the maximal slope of restitution curves at each site (P < 0.05 for all). APD alternans occurred at shorter pacing cycle length at each site during GPS when compared with baseline (P < 0.05 for all).

CONCLUSIONS

GPS prolonged ventricular ERP, decreased the slope of restitution curves and delayed APD alternans, indicating that GPS may exert a protective role for ventricular arrhythmias.