The role of atrial ectopics in initiating paroxysmal atrial fibrillation

Aims To characterize the nature and timing of atrial ectopics preceding cli nical episodes of paroxysmal atrial fibrillation. Methods and Results Holter recordings (n = 177. 60 patients. 58% male, mean age 61.7 +/- 11.5 years) were performed on patients with paroxysmal atrial fibrillation. These were subjected to standard analysis and recordings con taining atrial fibrillation episodes suitable for analysis were identified (n = 74). Beat interval files differentiating sinus rhythm from atrial fibr illation were generated and atrial ectopics were identified. Atrial ectopic s preceding atrial fibrillation were found to be more frequent (50.7 +/- 7. 39 min(-1)) and more premature (ratio of coupling interval to that of surro unding sinus cycles = 0.56 +/- 0.08) compared to ectopics occurring remote from atrial fibrillation episodes (frequency = 3.60 +/- 7.32 min(-1) P = 5 x 10(-24). prematurity ratio = 0.60 +/- 0.10, P = 2 x 10(-73)). Atrial ecto pic coupling interval frequency histograms were generated and analysed visu ally and by an automated statistically based test. Many ectopics were seen to occur at one coupling interval in 27 recordings (in eight this occurred only preceding atrial fibrillation onset. while in a further 19 cases this was also seen remote from atrial fibrillation onset). Overall 45% of ectopi cs preceding atrial fibrillation episodes occurred in isolation. 13%, as pa rt of a bigeminal rhythm, 22% as couplets and 20% as runs. This pattern did not differ from that seen remote from atrial fibrillation episodes. Conclusion Paroxysmal atrial fibrillation is preceded by ectopics of a fixe d coupling interval in a significant proportion of patients. If. as seems l ikely, this is a marker of 'focally mediated' atrial fibrillation. then Hol ter techniques may provide a useful screening tool with which to identify p atients suitable for fuller electrophysiological assessment. (Eur Heart J 2 001; 22: 333-339, doi:10.1053/euhj.2000.2517) (C) 2001 The European Society of Cardiology.