| Abstract: | Background: This study examined the possible role of atrial ectopics and short runs of atrial tachycardia in the initiation of episodes of paroxysmal atrial fibrillation (PAF). Methods: Holter recordings from patients participating in pharmacotherapy trials for the prevention of PAF were examined. Treatment comprised placebo, digoxin, disopyramide, or atenolol. The frequency of atrial ectopic beats during each 30 seconds over the 5 minutes prior to PAF and whether this was also associated with atrial tachycardia (3 or more ectopics in succession) was calculated. Results: The mean number of ectopics was 4.1 in the final minute, but patients receiving disopyramide or atenolol had significantly more ectopics than those on placebo (P > 0.05 for both). Those on digoxin had a similar number of ectopics to placebo patients. There was no relationship between heart rate at PAF onset and ectopic frequency, nor any association between the presence of one or more episodes of atrial tachycardia and ectopic frequency. Conclusion: Atrial ectopics increase in frequency prior to PAF onset, and this study suggests that antiarrhythmic therapy may increase the number of ectopics required to initiate PAF. |
