Key result
Autonomic blockade prolongs AVN effective refractory period ~6-fold more in adult versus young mice.
Why the study?
Does autonomic blockade alter rate-dependent AV nodal conduction and facilitation differently in young versus adult mice?
Population
Young (age 4-6 weeks; n = 11) and adult (age 8-9 months; n = 11) female mice
Comparison
Autonomic blockade vs Baseline (before autonomic blockade)
Design
Preclinical
Authors
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Age-dependent autonomic effects on AV nodal refractoriness seen in mice; hypothesis-generating and should not yet change clinical practice.
Does autonomic blockade alter rate-dependent AV nodal conduction and facilitation differently in young versus adult mice?
Absolute Event Rate: 21.4% vs 3.5%
p-value: p=0.002
Complete autonomic blockade significantly increases AVN conduction times and refractory periods in adult but not young mice, indicating age-dependent autonomic regulation of AV nodal properties.
Saba et al. (2003) studied this question. Autonomic blockade vs. Young mice and baseline was evaluated on Increase from baseline of AVN effective refractory period (deltaAVNERP) (p=0.002). Autonomic blockade resulted in a significantly larger increase in AVN effective refractory period in adult mice compared to young mice (21.4 vs 3.5 msec, P=0.002).
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