Objective: The objective of the study was to verify, if the particular sequence of electrical atrioventricular activation during tachycardia is associated with the development of atrial remodelling and predisposition to atrial fibrillation (AF) in patients with nodal reentry tachycardia (AVNRT).
Methods and results: We assessed 117 consecutive patients with AVNRT identified during electrophysiological study. Two groups were identified: the AF group, n = 21 (17.9%, median age 46.0, 15 women), with clinically documented AF, and the control group, n = 96, without AF (median age 48.5, 69 women). Tachycardia cycle length (VV), anterograde AV, retrograde VA activation intervals and indexes (AV/VV, VA/VV) during AVNRT, atrial refractory period (AERP), intraatrial (IntraCT) and interatrial conduction time (InterCT) of the sinus beat and premature stimuli were analysed. The longer retrograde and shorter anterograde activation was found in AF patients with typical AVNRT, the opposite relations showed the subjects with atypical tachycardia. Intra and InterCT of sinus beat, and of paced extrastimuli were longer, AERP was borderline shorter in the AF-group than in the controls. The longest conduction times and shortest AERP were seen in the patients with VA/VV within 20-40% of the tachycardia cycle, this group comprised 71% of all AF-patients (P< 0.001).VA was predictive for AF in typical (OR/unit 1.04) and atypical AVNRT (OR/unit 0.93, P< 0.05).
Conclusions: The particular sequence of electrical atrioventricular activation, seen in some patients during AVNRT, is associated with disturbances of atrial conduction, refractoriness and predisposes to atrial fibrillation.