Role of autonomic tone in facilitating spontaneous onset of typical atrial flutter.

OBJECTIVES This study sought to study the change in autonomic tone that precedes the initiation of paroxysmal atrial flutter. BACKGROUND An abrupt change in the autonomic tone of the heart is an important initiating factor in the pathogenesis of ventricular tachyarrhythmias and paroxysmal atrial fibrillation. Whether the autonomic tone has a role in the initiation of paroxysmal atrial flutter has not been reported. METHODS Holter electrocardiographic recording was used to investigate the changes in heart rate variability before the onset of paroxysmal atrial flutter. RESULTS A total of 12 patients with paroxysmal atrial flutter were analyzed. An increase in the normalized value of the low frequency (LF) component and the LF/high frequency (HF) ratio and a decrease in the normalized value of the HF component began at 6 min before the onset of episodes of paroxysmal atrial flutter, which indicated that sympathovagal balance had shifted to more sympathetic predominance. CONCLUSIONS An increase in sympathetic modulation or vagal withdrawal, or both, may facilitate the initiation of atrial flutter.