Chronic atrial flutter in an ovine model significantly reduced right atrial conduction velocity (from 89 to 64 cm/s, P<0.001) and refractoriness, creating a substrate for sustained AF.
Does chronic atrial flutter lead to electrical remodeling and atrial fibrillation in an ovine model?
In an ovine model, sustained atrial flutter causes electrical remodeling that creates a substrate for atrial fibrillation, though spontaneous conversion requires specific triggers.
Absolute Event Rate: 64% vs 89%
p-value: p=<0.001
BACKGROUND: Atrial flutter (AFL) and atrial fibrillation (AF) frequently coexist, yet the specific relationship between these arrhythmias, and particularly whether sustained AFL leads to AF, is unknown. METHODS AND RESULTS: We investigated the electrophysiological consequences of chronic AFL using an ovine anatomic right atrial Y-lesion model. AFL was induced in 7 animals, and 4 remained in sinus rhythm (controls). Sheep were monitored for spontaneous conversion of AFL to AF. Six of 7 sheep sustained AFL for 28 days. In 1 of 7 sheep, spontaneous conversion of AFL to AF occurred on day 5. AFL produced a highly significant fall in right and left atrial refractoriness (AERP, P30 seconds) was not inducible at baseline but after 28 days of AFL could be induced in 6 of 6 sheep by critically timed single or multiple extrastimuli delivered either in sinus rhythm or AFL. There was no significant change in any parameter in control sheep. CONCLUSIONS: In this model, AFL produced electrical remodeling and the substrate for sustained AF. However, spontaneous conversion to AF was uncommon, and the development of AF was dependent on specific triggers.
Morton et al. (Tue,) conducted a other in Atrial flutter (n=11). Induced atrial flutter vs. Sinus rhythm (controls) was evaluated on Right atrial conduction velocity (cm/s) (p=<0.001). Chronic atrial flutter in an ovine model significantly reduced right atrial conduction velocity (from 89 to 64 cm/s, P<0.001) and refractoriness, creating a substrate for sustained AF.
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