Effect of autonomic blockade on ventricular refractoriness and atrioventricular nodal conduction in humans. Evidence supporting a direct cholinergic action on ventricular muscle refractoriness.
Why the study?
Does autonomic blockade with propranolol and atropine affect ventricular refractoriness and AV nodal conduction in humans?
Population
13 human subjects
Comparison
Autonomic blockade with propranolol plus atropine vs Control state (baseline)
Design
Other
Authors
Discussion
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Member takes
Implication
Vagal tone may prolong ventricular refractoriness despite beta-blockade; leaves open clinical relevance for arrhythmia risk.
Structured PICO
Does autonomic blockade with propranolol and atropine affect ventricular refractoriness and AV nodal conduction in humans?
P
Population
13 human subjects
I
Intervention
Autonomic blockade with propranolol (0.15 mg/kg, iv) plus atropine (0.03 mg/kg, iv)
C
Comparator
Control state (baseline)
O
Outcome
Ventricular effective (ERP) and functional (FRP) refractory periods, and AV nodal conduction (shortest atrial pacing cycle length sustaining 1:1 AV nodal conduction)surrogate
Resting vagal tone exerts a significant effect on human ventricular refractoriness even during beta-adrenergic blockade, while vagal and adrenergic tone have a balanced effect on resting AV nodal conduction.
Cite This Study
Prystowsky et al. (1981) studied this question.