the cell, there is a decrease in electrical signals for contraction, thus allowing time for the heart's natural pacemaker to rectify arrhythmic contractions. Secondly, lower calcium means a decrease in strength and rate of the contractions, which can be helpful in treatment of abnormally fast heart rates. Type III antiarrhythmic action Sotalol also acts on potassium channels and causes a delay in relaxation of the ventricles. By blocking these potassium channels, sotalol inhibits efflux of K+ ions, which results in an increase in the time before another electrical signal can be generated in ventricular myocytes. This increase in the period before a new signal for contraction is generated, helps to correct arrhythmias by reducing the potential for premature or abnormal contraction of the ventricles but also prolongs the frequency of ventricular contraction to help treat tachycardia. History Sotalol was first synthesized in 1960 by A. A. Larsen of Mead-Johnson Pharmaceutical. It was originally recognized for its blood pressure lowering effects and its ability to reduce the symptoms of angina. It was made available in the United Kingdom and France in 1974, Germany in 1975, and Sweden in 1979. It became widely used in the 1980s. In the 1980s, its antiarrhythmic properties were discovered. The United States approved the drug in 1992. Brand names Trade names for Sotalol include Betapace and Betapace AF (Berlex Laboratories), Sotalex and Sotacor (Bristol-Myers Squibb), and Sotylize (Arbor Pharmaceuticals). References External links Antiarrhythmic agents Beta blockers Sulfonamides Orphan drugs Potassium channel blockers Phenylethanolamines Peripherally selective drugs Isopropyl compounds Wikipedia medicine articles ready to translate