- Esmolol is a very short acting,
cardioselective beta-adrenergic receptor
antagonist.
- i.v. administration is
used for rapid beta-receptor blockade (often for
treatment of atrial fibrillation with high
ventricular following rates)
- Antiarrhythmic effects
are due mainly to beta-adrenergic receptor
blockade. Normally, sympathetic drive results in
increased in Ca2+ , K+and
Cl- currents.
- Increased sympathetic tone also
increases phase 4 depolarization (heart rate goes
up), and increases DAD (delayed
afterdepolarizations) and EAD (early
afterdepolarization) mediated arrhythmias. These
effects are blocked by beta-adrenergic receptor
blockers.
- Beta-adrenergic receptor
blockers
- increase AV
conduction time
- increase AV nodal
refractoriness, thereby helping to
terminate nodal reentrant arrhythmias.
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