Title:Chemistry, Physiology, and Pharmacology of β-Adrenergic Mechanisms in the Heart. Why are β-Blocker Antiarrhythmics Superior?
Volume: 21
Issue: 8
Author(s): A. Jozsef Szentmiklosi, Norbert Szentandrassy, Bence Hegyi, Balazs Horvath, Janos Magyar, Tamas Banyasz and Peter P. Nanasi
Affiliation:
Keywords:
β-adrenergic receptors, β-receptor blockers, proarrhythmic mechanisms, antiarrhythmic drugs, cardiac ion currents, cardiac remodeling.
Abstract: Stimulation of β-adrenergic receptors in the heart is the most effective endogenous way to increase the mechanical performance
of cardiac tissues to meet the requirements of a fight-or-flight situation or stress. On the other hand, sustained activation of cardiac
β-receptors initiates maladaptive remodeling of the myocardium leading to cardiomyopathies and heart failure. Since both acute and
chronic stimulation of β-adrenoceptors are arrhythmogenic, the application of β-receptor blockers exerts effective antiarrhytmic actions at
both short and long time scale. Compared to other classes of antiarrhythmic agents, β-blockers are the class of antiarrhythmics that was
shown to decrease mortality in postinfarct patients. Chemical, physiological, and pharmacological properties of the β-adrenoceptor related
signaling, the role of β-1, β-2, and β-3 receptor subtypes, consequences of acute and long term β-adrenergic stimulation and the underlying
proarrhythmic mechanisms, including the changes in cardiac ion currents and Ca2+ handling, are reviewed in this paper together
with the clinical relevance of cardioprotective β-blocking therapy.
