Key result
Continuous rapid atrial pacing led to a higher rate of sustained atrial fibrillation compared to intermittent burst-pacing (77% vs 29%, P<0.05) in a sheep model.
Why the study?
Does continuous rapid atrial pacing compared to intermittent burst-pacing increase the induction of sustained atrial fibrillation in a sheep model?
Does continuous rapid atrial pacing compared to intermittent burst-pacing increase the induction of sustained atrial fibrillation in a sheep model?
Limiting atrial arrhythmia burden in a sheep model reduced the development of sustained AF, which was associated with less atrial dilation and conduction slowing rather than differences in atrial refractoriness.
Answers are grounded in this paper and cite their sources.
May support limiting arrhythmia burden to curb sustained AF in models; leaves open clinical translation.
In different animal models rapid atrial stimulation led to a shortening and maladaptation to rate of the atrial effective refractory period (AERP). This atrial electrical remodeling resulted in an increased vulnerability to atrial fibrillation (AF). These experimental findings formed the rationale for a stringent pursuit of sinus rhythm in patients with AF, since this would prevent or reverse atrial remodeling. This study tested the hypothesis that a reduction of arrhythmia burden would lead to a decreased vulnerability for AF. Different rapid atrial pacing protocols in a sheep model were used. During 15 weeks, 13 animals were continuously rapid paced and 7 animals were intermittently burst-paced, resulting in rapid atrial activation during 100% versus 33 +/- 4% of the time, respectively. In the continuously paced group, 77% of the animals developed sustained AF (i.e., > 1 hour) versus only 29% in the burst-paced group (P < 0.05). However, there was no difference in mean AERP shortening over time, nor maximal AERP shortening per animal, between both protocols. Minimal AERP was 103 +/- 5 ms in the continuously paced group and 107 +/- 5 in the burst-paced group (P = NS). Significant changes could be identified in effect on P wave duration, AVN function, and atrial dilation. Conduction slowing was more pronounced in the continuously paced group with a maximal P wave duration of 136 +/- 4 ms in this group versus 116 +/- 5 in the burst-paced group (P < 0.05). In the continuously paced group, the right atrial area significantly increased from 2.5 +/- 0.1 cm2 at baseline to 4.2 +/- 0.2 cm2. In the burst-paced group there was no significant atrial dilatation (from 2.6 +/- 0.1 to 2.8 +/- 0.1 cm2). In conclusion, limiting atrial arrhythmia burden slowed the development of sustained AF in this sheep model. This was not mediated by a decreased influence on atrial refractoriness but seemed to be dependent on smaller changes in atrial conduction and dimensions.
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Willems et al. (2001) studied Atrial fibrillation (n=20). Continuous rapid atrial pacing vs. Intermittent burst-pacing was evaluated on Development of sustained AF (> 1 hour) (p=< 0.05). Continuous rapid atrial pacing led to a higher rate of sustained atrial fibrillation compared to intermittent burst-pacing (77% vs 29%, P<0.05) in a sheep model.
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