ATRIAL PREMATURE BEATS COUPLING INTERVAL DETERMINES LONE PAROXYSMAL ATRIAL-FIBRILLATION ONSET

In 20 patients with recurrent episodes of lone paroxysmal atrial fibrillation we assessed the onset pattern of each episode of either atrial fibrillation or of atrial flutter during a 24-h Holter monitoring. We evaluated 24 twenty-four-hour Holter tape recordings and our data are related to 168 episodes of paroxysmal atrial fibrillation and 27 episodes of paroxysmal atrial flutter. Eighty-five percent of atrial fibrillations and 67% of atrial flutters were of short duration (< 5 min). The majority of patients (80%) had either nocturnal or daily episodes of arrhythmia and PP intervals immediately before onset of arrhythmia did not show significant variations in 77% of cases. The coupling interval of the supraventricular premature beats eliciting atrial fibrillation was significantly shorter than the coupling intervals of the spontaneous isolated supraventricular premature beats (p < 0.0001); again, in 6 patients with either atrial fibrillation or flutter, the coupling interval at onset of fibrillation was significantly shorter in comparison to flutter (p < 0.0001). In conclusion, vagal or sympathetic prevalence does not seem to influence significantly the beginning of the arrhythmia, while the coupling interval of the atrial premature beats plays a critical role in the inducibility of atrial flutter or fibrillation.