Sotalol is a beta-blocker that affects the heart and circulation (blood flow through arteries and veins). Sotalol is used to help keep the heart beating normally in people with certain heart rhythm disorders of the ventricles (the lower chambers of the heart that allow blood to flow out of the heart). Sotalol is used in people with ventricular tachycardia or ventricular fibrillation. Another form of this medicine, called sotalol AF, is used to treat heart rhythm disorders of the atrium (the upper chambers of the heart that allow blood to flow into the heart). Sotalol AF is used in people with atrial fibrillation or atrial flutter. Sotalol (Betapace, Sorine, Sotylize) is not used for the same conditions that sotalol AF (Betapace AF) is used for. Sotalol may also be used for purposes not listed in this medication guide.