Neural mechanisms of atrial arrhythmias.
The past 5 years have seen great advances in the knowledge of neural mechanisms of atrial arrhythmogenesis. Direct autonomic nerve recordings demonstrate that simultaneous sympathovagal discharges and intrinsic cardiac nerve activities are common triggers of paroxysmal atrial tachycardia and atrial fibrillation. While activity of the autonomous nervous system (ANS) is crucial in triggering paroxysmal atrial fibrillation, a high incidence of sympathovagal co-activation at baseline is associated with a high vulnerability to pacing-induced sustained atrial fibrillation, suggesting that ANS has a role in the development of persistent atrial fibrillation. Modulation of ANS activity may constitute an important therapeutic strategy for the management of atrial tachyarrhythmias. Specifically, continuous, low-level stimulation of the left cervical vagus nerve effectively suppresses atrial tachyarrhythmias by reducing the nerve activity of the stellate ganglion. Clinically, compared with pulmonary vein isolation alone, the addition of ablation of intrinsic cardiac ganglia may confer better outcomes for patients with paroxysmal atrial fibrillation. These findings suggest that further investigation of the neural mechanisms of atrial arrhythmias might lead to better management of patients with atrial arrhythmias. In this article, we review the role of the ANS in the induction and maintenance of atrial arrhythmias and the role of neural modulation as a treatment strategy for atrial arrhythmias.