Pharmacologic autonomic blockade with esmolol and atropine significantly decreased mean dominant frequency (5.61 to 5.43 Hz, P<0.001) and median continuous activity (31% to 26%) in patients with AF.
Observational (n=17)
Does pharmacologic autonomic blockade alter dominant frequency and continuous activity of atrial electrograms in patients with atrial fibrillation?
Pharmacologic autonomic blockade with esmolol and atropine acutely decreases dominant frequency and continuous activity in patients with atrial fibrillation, highlighting the role of autonomic tone in AF electrophysiology.
Absolute Event Rate: 5.43% vs 5.61%
p-value: p=<0.001
BACKGROUND: Ablation of atrial autonomic inputs exerts antifibrillatory effects. However, because ablation destroys both myocardium and nerve cells, the effect of autonomic withdrawal alone remains unclear. We therefore examined the effects of pharmacologic autonomic blockade (PAB) on frequency and fractionation in patients with atrial fibrillation (AF). METHODS: Esmolol and atropine were administered and electrograms were recorded simultaneously from both atria and the coronary sinus. In 17 patients, AF was recorded for 5 minutes and dominant frequency (DF) and continuous activity (CA) were compared before and during PAB. RESULTS: Examination of the pooled data (537 sites, 17 patients) revealed a statistically significant decrease in mean DF (5.61–5.43Hz, P < 0.001) during PAB. Site-by-site analysis showed that 67% of sites slowed (0.45 ± 0.59 Hz), whereas 32% accelerated (0.49 ± 0.59Hz). Fractionation was reduced: median CA decreased from 31% to 26% (P < 0.001). In patient-by-patient analysis, mean DF/median CA decreased in 13 of 17 patients and increased in four. The spatial heterogeneity of DF decreased in nine of 17 patients (spatial coefficient of variation of DF at "nondriver sites" decreased by a mean of 2%). CONCLUSION: PAB decreases DF and CA in the majority of sites. Given the complexity of interactions between atrial cells during AF, the effects of PAB on DF and fractionation are more heterogeneous than the effects of PAB on isolated cells.
Habel et al. (Thu,) conducted a observational in Atrial fibrillation (n=17). Pharmacologic autonomic blockade (Esmolol and atropine) vs. Before pharmacologic autonomic blockade was evaluated on Mean dominant frequency (DF) in Hz (p=<0.001). Pharmacologic autonomic blockade with esmolol and atropine significantly decreased mean dominant frequency (5.61 to 5.43 Hz, P<0.001) and median continuous activity (31% to 26%) in patients with AF.
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