Modification of supraventricular tachyarrhythmias by stimulating atrial neurons

The effects of stimulating the right atrial ventral ganglionated plexus on ventricular performance during atrial tachycardia was studied in 8 lightly sedated (pentobarbital, 2.5 mg/kg intravenously) dogs with sterile pericarditis. Atrial arrhythmias were induced by electrical stimulation (10 V, 4 ms, 100 Hz) of the right atrium through previously inserted temporary bipolar pacemaker wires. Various types of supraventricular tachycardias were produced. Atrial fibrillation was produced in 3 dogs, atrial tachycardia in all 8 dogs, different atrioventricular nodal ectopic rhythms in 6 dogs, and atrial flutter in 1 dog. These arrhythmias were associated with irregular ventricular contractions that resulted in low ventricular pressures during many cardiac cycles such that low or no aortic pressure was generated. Right atrial ventral ganglionated plexus stimulation induced slowing of ventricular rate so that every ventricular contraction resulted in aortic pressure generation, thus increasing mean aortic pressure. Responses elicited by atrial ganglionated plexus stimulation were eliminated after atropine administration. We conclude that electrical stimulation of the right atrial ventral ganglionated plexus results in slowing of ventricular contractile rate during supraventricular tachycardia, presumably by activating efferent vagal neuronal elements, thereby improving ventricular performance. If applicable in humans, this technique may be of use in management of postoperative atrial arrhythmias after cardiac operations.